Myanmar SMS Guide: Best Practices, Compliance, and Features

Send SMS messages to Myanmar (+95) in full compliance with local telecommunications regulations. This guide covers sender ID registration (11-day process), operator-specific requirements for MPT, Ooredoo, and Telenor Myanmar, Unicode (UCS-2) encoding for Burmese language, Telecommunications Law 2013 compliance, and API integration examples.

Myanmar SMS Market Overview

Market Conditions: Three major operators dominate Myanmar's mobile market: MPT (Myanmar Posts and Telecommunications), Ooredoo, and Telenor Myanmar. Urban areas favor OTT messaging apps like Viber and Facebook Messenger, but SMS remains essential for business communications and authentication – especially in rural regions where Android devices significantly outnumber iOS. Use SMS to reach Myanmar's broader population effectively.

Cost Comparison by Operator:

Key SMS Features and Capabilities in Myanmar

Myanmar supports comprehensive SMS functionality including two-way messaging and concatenated messages, though with specific restrictions and requirements for different sender ID types.

Two-way SMS Support

Myanmar supports two-way SMS across all major mobile networks with no special restrictions, making it suitable for customer service and interactive campaigns.

Common use cases:

• Customer service inquiries and support
• Survey responses and feedback collection
• Appointment confirmations and rescheduling
• Order status updates with reply options

Technical setup: Configure webhook endpoints to receive inbound messages and process them within your application. Response times vary by network but typically occur within seconds.

Concatenated Messages (Segmented SMS)

Support: Yes, concatenation is supported across most networks, though some limitations exist for certain sender ID types, particularly with MyTel network.

Message length rules:

• GSM-7 encoding: 160 characters per segment
• Unicode (UCS-2): 70 characters per segment

Encoding considerations: Both GSM-7 and UCS-2 encodings are supported. UCS-2 is required for Myanmar language (Burmese) characters.

Cost implications: Carriers charge per segment. A 320-character GSM-7 message counts as 2 segments. A 140-character Unicode message counts as 2 segments. Plan your message length accordingly to manage costs.

Character count examples:

• "Your OTP is 123456. Valid for 10 minutes." (46 chars, GSM-7) = 1 segment
• "သင့်OTP မှာ 123456 ဖြစ်သည်။ ၁၀ မိနစ်အတွင်း အသုံးပြုပါ။" (52 chars, UCS-2) = 1 segment
• Mixed content defaults to UCS-2 encoding

MMS Support

MMS messages are automatically converted to SMS with an embedded URL link. This conversion ensures broader compatibility and reliable delivery across all Myanmar networks. Host media content on a secure, mobile-optimized platform and include short URLs in messages.

Technical specifications:

• Maximum file size before conversion: 500 KB
• Supported formats: JPEG, PNG, GIF (images); MP4, 3GP (video)
• URL shortening recommended (< 20 characters)
• HTTPS hosting required for security

Recipient Phone Number Compatibility

Number Portability

Number portability is not available in Myanmar. Phone numbers remain tied to their original mobile network operator, simplifying message routing and delivery.

Carrier Identification by Number Prefix:

Sending SMS to Landlines

Sending SMS to landline numbers is not supported in Myanmar. Attempts to send messages to landline numbers result in a 400 response with error code 21614, and such messages will not appear in logs or incur charges.

Identifying mobile vs. landline numbers: Mobile numbers in Myanmar start with +959 followed by 7–9 digits. Landline numbers use different prefixes (e.g., +951 for Yangon, +952 for Mandalay). Validate number format before sending to avoid errors.

Compliance and Regulatory Guidelines for SMS in Myanmar

The Telecommunications Law 2013, overseen by the Posts and Telecommunications Department under the Ministry of Transport and Communications (MOTC), governs SMS communications in Myanmar. All SMS marketing activities must comply with these regulations and obtain necessary approvals.

Consent and Opt-In

Explicit Consent Requirements:

• Obtain written or electronic consent before sending marketing messages
• Maintain consent records and make them easily accessible
• Clearly state the purpose of communication during opt-in
• Use double opt-in for marketing campaigns (recommended)

Best Practices for Documentation:

• Store consent timestamps and methods
• Maintain detailed opt-in source records
• Audit your consent database regularly
• Enable easy access to consent history
• Retain consent records for minimum 3 years (industry standard)

Sample consent form language: "I agree to receive SMS messages from [Company Name] about [specific purpose]. I can opt out at any time by replying STOP. Message rates may apply."

HELP/STOP and Other Commands

• Include clear opt-out instructions in all marketing messages
• Support required keywords: STOP, CANCEL, UNSUBSCRIBE (in English)
• Support Myanmar language equivalents: ရပ်ဆိုင်း (STOP), ဖျက်သိမ်း (CANCEL)
• Provide service information and contact details via HELP command
• Respond to opt-out commands immediately in the same language as the original message

Technical implementation: Configure your SMS platform to detect keywords (case-insensitive) and automatically update your subscriber database. Send confirmation messages within 60 seconds of receiving opt-out requests.

Do Not Call / Do Not Disturb Registries

Myanmar does not maintain a centralized Do Not Call registry. Maintain your own compliance:

• Maintain your own suppression lists
• Honor opt-out requests within 24 hours
• Implement proper screening mechanisms
• Clean up your contact databases regularly
• Document all opt-out requests and actions taken

Time Zone Sensitivity

• Observe quiet hours: 22:00–06:00 Myanmar Time (MMT, UTC+6:30)
• Emergency messages are exempt from time restrictions
• Consider religious and cultural holidays
• Send messages during the recommended window: 09:00–20:00 MMT

Major holidays to avoid:

• Thingyan (Myanmar New Year): April 13–16
• Independence Day: January 4
• Union Day: February 12
• Thadingyut Festival: October (full moon)
• Tazaungdaing Festival: November (full moon)

Emergency message definition: Messages related to urgent security notifications, critical service disruptions, fraud alerts, or life-threatening situations qualify as emergency messages exempt from quiet hours.

Phone Numbers Options and SMS Sender Types for Myanmar

Alphanumeric Sender ID

Operator network capability: Supported by all operators except MyTel

Registration requirements: Pre-registration required with 11-day provisioning time

Sender ID preservation: Yes, except for MyTel network where it may be modified

Registration process:

1. Submit application to Posts and Telecommunications Department
2. Provide company registration documents and business license
3. Specify intended sender ID (3–11 alphanumeric characters)
4. Pay registration fee (contact MOTC for current rates)
5. Await approval (11 business days average)
6. Renew annually

Character limits and formatting:

• Length: 3–11 characters
• Allowed: A–Z (uppercase), a–z (lowercase), 0–9
• No spaces or special characters
• Cannot be all numeric (would appear as long code)

Long Codes

Domestic vs. International:

• Domestic: Supported for P2P messaging only
• International: Not supported

Sender ID preservation: Yes for domestic numbers

Provisioning time: Immediate for domestic numbers

Use cases: Limited to person-to-person communications

P2P vs. A2P distinction: Person-to-Person (P2P) messaging is informal communication between individuals. Application-to-Person (A2P) is commercial messaging from businesses to consumers. A2P requires alphanumeric sender IDs or short codes in Myanmar.

Short Codes

Support: Not currently supported in Myanmar

Provisioning time: N/A

Use cases: N/A

Short code availability is under regulatory review. Check with MOTC for updates on future implementation timelines.

Restricted SMS Content, Industries, and Use Cases

Restricted Industries:

• Gambling and betting services
• Adult content and services
• Unauthorized financial services
• Political campaign messages without proper authorization
• Cryptocurrency promotions

Political message authorization: Obtain approval from the Union Election Commission (UEC) before sending political campaign messages. Submit campaign plans and message templates 30 days before sending.

Unauthorized financial services definition: Financial services operating without license from the Central Bank of Myanmar, including unlicensed lending, investment schemes, and money transfer services.

Regulated Industries:

• Banking and financial services require Central Bank of Myanmar approval
• Healthcare messages must comply with Ministry of Health guidelines
• Insurance services need approval from Financial Regulatory Department

Approval process timelines:

• Banking/Financial: 30–45 days (Central Bank of Myanmar)
• Healthcare: 15–30 days (Ministry of Health)
• Insurance: 20–30 days (Financial Regulatory Department)

Contact information for regulatory bodies:

• Central Bank of Myanmar: cbm.gov.mm
• Ministry of Health: mohs.gov.mm
• Posts and Telecommunications Department: ptd.gov.mm

Content Filtering

Known Carrier Filters:

• URLs from unknown domains (not whitelisted)
• Multiple exclamation marks (> 3 in a message)
• ALL CAPS messages (> 50% of content)
• Excessive special characters (> 10% of content)

Specific thresholds:

• Exclamation marks: Maximum 3 per message
• Capitalization: Keep below 50% of total characters
• Special characters: Keep below 10% of total characters
• Unknown URLs: Use registered shorteners or whitelist your domain

Appeals process: Contact your SMS provider's support team with message details and delivery failure logs. Providers can submit whitelist requests to carriers on your behalf. Resolution typically takes 3–5 business days.

Best Practices:

• Use registered URL shorteners (bit.ly, tinyurl.com)
• Avoid spam trigger words (FREE, WINNER, URGENT, CLICK NOW, LIMITED TIME)
• Maintain consistent sender IDs
• Keep content professional and clear

Common spam trigger words in Myanmar context: အခမဲ့ (free), ဆုလာဘ် (prize), အမြန် (urgent), ကန့်သတ်ချိန် (limited time), အခုပဲ (now only)

Best Practices for Sending SMS in Myanmar

Messaging Strategy

• Limit messages to 160 characters when possible to minimize costs and ensure complete display
• Include a clear call-to-action to drive engagement
• Use your company name in the sender ID for brand recognition
• Avoid excessive punctuation to prevent carrier filtering

Message template examples:

Appointment Reminder: "[ClinicName]: Your appointment is on Jan 15 at 2 PM. Reply C to confirm or R to reschedule. Call 01-234567 for help."

Order Confirmation: "[StoreName]: Order #12345 confirmed. Estimated delivery: Jan 16. Track at: [short-link]. Questions? Call 09-87654321."

OTP Verification: "Your [AppName] verification code is 456789. Valid for 10 minutes. Do not share this code with anyone."

Sending Frequency and Timing

• Send maximum 4 marketing messages per month per user (industry best practice)
• Respect religious holidays and festivals
• Avoid sending during major national events
• Space out messages across your campaign duration (minimum 7 days between messages)

Source for 4 messages/month limit: This follows CTIA Messaging Principles and Best Practices (international standard), adapted for Myanmar market conditions based on carrier recommendations.

Religious holidays and national events:

• Thingyan: April 13–16 (avoid 5 days before and 2 days after)
• Buddhist Lent: July–October (reduce frequency)
• Tazaungdaing: November (full moon day ± 2 days)
• Christmas: December 25 (for Christian recipients)
• Eid al-Fitr/Eid al-Adha: (dates vary, for Muslim recipients)

Localization

• Support both Myanmar language and English
• Use Unicode (UCS-2) encoding for Myanmar text
• Consider regional language variations
• Test message rendering on different devices

Regional dialect considerations: While Standard Burmese is understood nationwide, consider regional variations in Shan, Karen, and Rakhine areas. Use neutral, formal language for broader appeal.

Device testing checklist:

• Test on Android devices (Samsung, Huawei, Oppo – most common in Myanmar)
• Test on iOS devices (iPhone X and later)
• Verify Unicode rendering on feature phones
• Check message display on 4-inch and 6-inch screens
• Confirm URL links are clickable
• Test with both Myanmar and English content

Opt-Out Management

• Process opt-outs within 24 hours (maximum)
• Maintain a centralized opt-out database
• Provide confirmation of opt-out
• Audit opt-out compliance regularly (monthly minimum)

Technical implementation guidance: Implement a database table with fields: phone_number, opt_out_date, opt_out_method, confirmation_sent, and campaign_id. Set up automated processes to sync this table with your messaging platform's suppression list every 6 hours.

Testing and Monitoring

• Test across all major carriers (MPT, Ooredoo, Telenor)
• Monitor delivery rates by carrier
• Track engagement metrics
• Report performance regularly

Testing procedures:

1. Send test messages to 3–5 numbers on each carrier
2. Verify sender ID display correctly
3. Check Unicode rendering for Myanmar text
4. Confirm delivery within 30 seconds
5. Test opt-out keywords and responses
6. Validate callback URLs receive delivery receipts

KPI benchmarks and performance targets:

• Delivery rate: > 95% (target: 98%)
• Delivery time: < 30 seconds average
• Opt-out rate: < 0.5% per campaign
• Click-through rate (with URLs): 5–15%
• Response rate (two-way): 10–25%

SMS API integrations for Myanmar

Twilio

Twilio provides robust SMS capabilities for Myanmar through their REST API. Authentication requires your Account SID and Auth Token.

import * as Twilio from 'twilio';

// Initialize Twilio client
const client = new Twilio(
  process.env.TWILIO_ACCOUNT_SID,
  process.env.TWILIO_AUTH_TOKEN
);

async function sendSMSToMyanmar() {
  const maxRetries = 3;
  let attempt = 0;

  while (attempt < maxRetries) {
    try {
      // Myanmar numbers must start with +95
      const message = await client.messages.create({
        body: 'Your message in Unicode or GSM-7 format',
        to: '+959XXXXXXXXX',  // Myanmar format
        from: 'YOUR_SENDER_ID', // Pre-registered alphanumeric sender ID
        // Optional parameters for Myanmar
        statusCallback: 'https://your-callback-url.com/delivery',
        provideFeedback: true
      });

      console.log(`Message sent successfully: ${message.sid}`);
      return message;
    } catch (error: any) {
      attempt++;

      if (error.code === 21614) {
        console.error('Invalid number format or landline');
        throw error; // Don't retry for invalid numbers
      }

      if (error.code === 20429 || error.status === 429) {
        // Rate limit hit - implement exponential backoff
        const waitTime = Math.pow(2, attempt) * 1000;
        console.log(`Rate limited. Waiting ${waitTime}ms before retry ${attempt}/${maxRetries}`);
        await new Promise(resolve => setTimeout(resolve, waitTime));
        continue;
      }

      if (attempt >= maxRetries) {
        console.error('Error sending message after retries:', error);
        throw error;
      }
    }
  }
}

// Callback URL implementation example
// POST endpoint to receive delivery receipts
app.post('/delivery', (req, res) => {
  const { MessageSid, MessageStatus, To, ErrorCode } = req.body;

  console.log(`Message ${MessageSid} to ${To}: ${MessageStatus}`);

  if (ErrorCode) {
    console.error(`Delivery failed with error code: ${ErrorCode}`);
  }

  // Update your database with delivery status
  // updateMessageStatus(MessageSid, MessageStatus);

  res.sendStatus(200);
});

Sinch

Sinch offers direct carrier connections in Myanmar. Their API requires API Token and Service Plan ID.

import { SinchClient } from '@sinch/sdk-core';

const sinchClient = new SinchClient({
  projectId: 'YOUR_PROJECT_ID',
  apiToken: 'YOUR_API_TOKEN'
});

async function sendSMSViaSinch() {
  try {
    const response = await sinchClient.sms.batches.send({
      sendSMSRequestBody: {
        to: ['+959XXXXXXXXX'],
        from: 'YOUR_SENDER_ID',
        body: 'Your message content',
        // Myanmar-specific parameters
        encoding: 'UCS2', // For Myanmar language
        deliveryReport: 'summary'
      }
    });

    console.log('Batch ID:', response.id);
    return response;
  } catch (error) {
    console.error('Sinch SMS Error:', error);
    throw error;
  }
}

// Batch sending recommendations
async function sendBatchSMS(recipients: string[], message: string) {
  // Recommended batch size: 1,000 recipients per batch
  const batchSize = 1000;
  const batches = [];

  for (let i = 0; i < recipients.length; i += batchSize) {
    const batch = recipients.slice(i, i + batchSize);
    batches.push(batch);
  }

  // Send batches with delay to avoid rate limits
  for (const batch of batches) {
    await sendSMSViaSinch();
    await new Promise(resolve => setTimeout(resolve, 1000)); // 1 second delay
  }
}

MessageBird

MessageBird provides reliable SMS delivery in Myanmar with strong delivery reporting.

import messagebird from 'messagebird';

const messageBirdClient = messagebird('YOUR_ACCESS_KEY');

async function sendSMSViaMessageBird() {
  const params = {
    originator: 'YOUR_SENDER_ID',
    recipients: ['+959XXXXXXXXX'],
    body: 'Your message content',
    // Myanmar-specific options
    datacoding: 'unicode', // For Myanmar language
    reportUrl: 'https://your-callback-url.com/report'
  };

  return new Promise((resolve, reject) => {
    messageBirdClient.messages.create(params, (err, response) => {
      if (err) {
        console.error('MessageBird Error:', err);
        reject(err);
        return;
      }
      console.log('Message sent:', response.id);
      resolve(response);
    });
  });
}

Plivo

Plivo offers competitive rates and good coverage in Myanmar.

import plivo from 'plivo';

const client = new plivo.Client(
  'YOUR_AUTH_ID',
  'YOUR_AUTH_TOKEN'
);

async function sendSMSViaPlivo() {
  try {
    const message = await client.messages.create({
      src: 'YOUR_SENDER_ID', // Pre-registered
      dst: '+959XXXXXXXXX',
      text: 'Your message content',
      // Myanmar-specific options
      type: 'unicode', // For Myanmar language
      url: 'https://your-callback-url.com/status',
      method: 'POST'
    });

    console.log('Message UUID:', message.messageUuid);
    return message;
  } catch (error) {
    console.error('Plivo Error:', error);
    throw error;
  }
}

API Rate Limits and Throughput

Provider-specific rate limits:

• Twilio: 30 messages/second (default), up to 100 messages/second with approval
• Sinch: 50 messages/second (batch API), 10 messages/second (single API)
• MessageBird: 30 messages/second (default), customizable with enterprise plans
• Plivo: 20 messages/second (default), up to 60 messages/second with higher tiers

General guidelines:

• Batch processing recommended for volumes > 1,000/hour
• Implement exponential backoff for retry logic
• Queue messages during peak hours (09:00–20:00 MMT)

Exponential backoff example:

async function sendWithExponentialBackoff(
  sendFunction: () => Promise<any>,
  maxRetries: number = 5
) {
  for (let attempt = 0; attempt < maxRetries; attempt++) {
    try {
      return await sendFunction();
    } catch (error: any) {
      if (attempt === maxRetries - 1) throw error;

      const waitTime = Math.min(1000 * Math.pow(2, attempt), 30000);
      console.log(`Attempt ${attempt + 1} failed. Retrying in ${waitTime}ms`);
      await new Promise(resolve => setTimeout(resolve, waitTime));
    }
  }
}

Throughput Management Strategies:

• Use batch APIs when available
• Implement message queuing system (Redis, RabbitMQ, AWS SQS)
• Monitor delivery rates by carrier
• Adjust sending speed based on delivery success

Queue system architecture recommendations:

1. Use Redis for lightweight queuing (< 10,000 messages/day)
2. Use RabbitMQ for medium volume (10,000–100,000 messages/day)
3. Use AWS SQS or Azure Service Bus for high volume (> 100,000 messages/day)
4. Implement dead letter queues for failed messages
5. Set up worker processes to consume queue at controlled rate

Error Handling and Reporting

Common Error Codes:

Logging Best Practices:

• Log all API responses with timestamps
• Track delivery receipts and final status
• Monitor carrier-specific errors
• Implement automated alerts for high failure rates (> 5%)

Structured logging format example:

interface SMSLog {
  timestamp: string;
  messageId: string;
  recipient: string;
  sender: string;
  status: 'queued' | 'sent' | 'delivered' | 'failed';
  errorCode?: string;
  errorMessage?: string;
  carrier: 'MPT' | 'Ooredoo' | 'Telenor' | 'MyTel';
  segmentCount: number;
  cost: number;
}

function logSMSEvent(log: SMSLog) {
  console.log(JSON.stringify(log));
  // Send to logging service (e.g., CloudWatch, Datadog, ELK)
}

Frequently Asked Questions

What is Myanmar's country code for SMS messages?

Myanmar's country code is +95. When sending SMS messages to Myanmar from abroad, use +95 followed by the mobile number. Myanmar mobile numbers typically start with 9 after the country code (e.g., +959XXXXXXXXX). All international SMS must include the +95 prefix for proper delivery.

Which mobile operators serve Myanmar?

Myanmar has three major mobile network operators: MPT (Myanmar Posts and Telecommunications), Ooredoo Myanmar, and Telenor Myanmar. MyTel is a fourth operator with limited SMS support. MPT is the state-owned incumbent operator, while Ooredoo and Telenor entered the market in 2014. Test your SMS delivery across all three major carriers to ensure optimal reach.

Operator coverage and regional strength:

• MPT: Nationwide coverage, strongest in rural areas
• Ooredoo: Strong urban presence in Yangon and Mandalay
• Telenor: Balanced urban/rural coverage, competitive rural pricing
• MyTel: Limited coverage, primarily urban areas

Is number portability available in Myanmar?

No, number portability is not available in Myanmar. Phone numbers remain permanently tied to their original mobile network operator. This simplifies message routing since you can identify the carrier from the number prefix, but users cannot switch operators while keeping their phone number.

What encoding should I use for Burmese language SMS?

Use Unicode (UCS-2) encoding for all SMS messages containing Burmese (Myanmar language) characters. UCS-2 encoding limits each message segment to 70 characters instead of the standard 160 characters for GSM-7 encoding. Both encodings are supported, but UCS-2 is required for proper rendering of Myanmar script.

Mixed-content encoding guidance: If your message contains both English and Burmese characters, the entire message must use UCS-2 encoding. Keep messages under 70 characters to avoid segmentation costs. Consider sending English-only versions to reduce character usage when possible.

How long does sender ID registration take in Myanmar?

Alphanumeric sender ID registration in Myanmar requires 11 days for provisioning. Pre-register your sender IDs with all operators before launching campaigns. Plan accordingly and submit registration requests well in advance of your campaign start date. MyTel network may modify or not preserve registered sender IDs.

What are Myanmar's SMS quiet hours?

Myanmar's quiet hours are 22:00–06:00 Myanmar Time (MMT, UTC+6:30). Avoid sending marketing messages during this period to comply with regulations and respect recipients. The recommended sending window is 09:00–20:00 MMT. Emergency messages are exempt from time restrictions. Always consider religious holidays and major national events when scheduling campaigns.

Do I need consent for SMS marketing in Myanmar?

Yes, obtain written or electronic consent before sending marketing messages in Myanmar. The Telecommunications Law 2013 requires explicit consent for all commercial communications. Implement double opt-in for marketing campaigns, maintain detailed consent records with timestamps, and honor opt-out requests within 24 hours. Include clear opt-out instructions in every marketing message.

What are the penalties for SMS violations in Myanmar?

The Telecommunications Law 2013, overseen by the Posts and Telecommunications Department under the Ministry of Transport and Communications (MOTC), governs SMS penalties in Myanmar. Violations can result in service suspension, fines ranging from 500,000 MMK to 5,000,000 MMK (approximately $240–$2,400 USD), and legal action for serious offenses. Banking and financial services without Central Bank approval face particularly strict enforcement. Maintain comprehensive compliance documentation to avoid penalties.

Penalty escalation process:

1. First violation: Written warning and 30-day correction period
2. Second violation: Fine of 500,000–1,000,000 MMK
3. Third violation: Fine of 1,000,000–3,000,000 MMK and temporary suspension
4. Repeated violations: License revocation and fines up to 5,000,000 MMK

Enforcement example: In 2023, an unlicensed lending service was fined 3,000,000 MMK and suspended for 6 months for sending unsolicited SMS without proper consent or Central Bank authorization.

Recap and Additional Resources

Key Takeaways:

1. Pre-register your alphanumeric sender IDs (allow 11 days for provisioning)
2. Support both Myanmar and English languages in your messages
3. Respect quiet hours (22:00–06:00 MMT)
4. Implement proper opt-out handling across all campaigns
5. Monitor delivery rates by carrier to optimize performance

Implementation Timeline:

Total estimated timeline: 4–6 weeks from start to production launch

Implementation Checklist:

• Review regulatory requirements
• Register with MOTC
• Apply for sender ID registration (all operators)
• Implement consent management system
• Set up opt-out keyword processing
• Configure API integration with retry logic
• Test across MPT, Ooredoo, and Telenor networks
• Verify Unicode rendering for Myanmar text
• Set up delivery receipt logging
• Configure quiet hours enforcement
• Create suppression list database
• Test opt-out workflow end-to-end
• Launch pilot campaign with small audience
• Monitor KPIs and adjust strategy

Additional Information:

• Posts and Telecommunications Department
• Telecommunications Law 2013
• Myanmar Mobile Operators
• Twilio Documentation
• Sinch Documentation
• MessageBird Documentation
• Plivo Documentation

Community and Support:

• Twilio Community Forum
• Stack Overflow - Myanmar SMS
• Contact your SMS provider's support team for carrier-specific issues