SMS Delivery Issues

Troubleshoot SMS messages not being delivered to recipients.

Troubleshoot issues when SMS messages are not being delivered to recipients.

Common Causes

1. Country Code Configuration

The mobile country code format may be incorrect.

Solution:

  1. Go to SMS → Settings → General
  2. Check Mobile Field Configuration settings
  3. Try including or excluding the country code prefix
  4. Test sending again

2. Invalid Recipient Numbers

Phone numbers may be incorrectly formatted.

Checklist:

  • Verify the phone number is correct
  • Check for extra spaces or characters
  • Ensure proper country code format
  • Confirm the number is active

3. Incorrect Sender ID

The sender ID may not be configured properly or not approved by the gateway.

Solution:

  1. Go to SMS → Settings → Gateway
  2. Verify the Sender ID field
  3. Check with your gateway provider if the sender ID is approved

4. Insufficient Credit

Your SMS gateway account may have no credit remaining.

Solution:

  1. Check your gateway account balance
  2. Add credit if needed
  3. Enable Auto-Update Credit to see balance in WordPress

5. Gateway Connection Issues

The SMS gateway may be experiencing problems.

Checklist:

  • Check gateway provider status page
  • Verify API credentials are correct
  • Test gateway connection in settings
  • Check for any IP restrictions

Debugging Steps

Step 1: Check Outbox

  1. Go to SMS → Outbox
  2. Look for the message status
  3. Check for any error messages

Step 2: Enable Debug Mode

  1. Go to SMS → Settings → Advanced
  2. Enable Debug Mode
  3. Send a test message
  4. Check the debug log for errors

Step 3: Test with Different Number

Try sending to a different phone number to rule out recipient-specific issues.

Step 4: Verify Gateway Settings

  1. Go to SMS → Settings → Gateway
  2. Re-enter your API credentials
  3. Save and test connection

Gateway-Specific Issues

Twilio

  • Verify Account SID and Auth Token
  • Check if phone number is verified (trial accounts)
  • Ensure messaging service is configured

Nexmo/Vonage

  • Verify API Key and Secret
  • Check sender ID restrictions by country

Other Gateways

  • Consult gateway documentation
  • Contact gateway support

Still Having Issues?

If problems persist after trying these solutions:

  1. Check the WP SMS documentation
  2. Contact your SMS gateway provider
  3. Contact WP SMS support

Last updated: December 28, 2025