The Short Answer

To fix the “MMS Not Sending” issue in Twilio, advanced users can directly verify that the Media URL is correctly formatted and accessible, ensuring it meets Twilio’s requirements for MMS messaging. By checking the Media URL and adjusting the SMS API settings, users can resolve the issue and successfully send MMS messages.

Why This Error Happens

• Reason 1: The most common cause of the “MMS Not Sending” error is an incorrectly formatted or inaccessible Media URL, which prevents Twilio from retrieving the media content required for MMS messaging. According to Twilio’s documentation, a valid Media URL must be publicly accessible and have a valid MIME type.
• Reason 2: An edge case cause of this error is a misconfigured SMS API setting, such as an incorrect account SID or auth token, which can prevent Twilio from authenticating and sending MMS messages. For example, if the account SID is incorrect, Twilio will return a 404 error, indicating that the account does not exist.
• Impact: The “MMS Not Sending” error can significantly impact businesses that rely on MMS messaging for customer engagement, resulting in delayed or lost messages, and potentially affecting customer satisfaction. In a real-world scenario, a company like Uber, which uses Twilio for customer notifications, may experience a significant increase in support requests if MMS messages are not delivered promptly.

Step-by-Step Solutions

Method 1: The Quick Fix

1. Go to Settings > Messaging > MMS and verify that the Media URL is correctly formatted and accessible.
2. Toggle the MMS Converter option to Off, as this feature can sometimes cause issues with Media URLs.
3. Refresh the page to apply the changes and test MMS messaging again.

Method 2: The Command Line/Advanced Fix

For advanced users, you can use the Twilio CLI to update the Media URL and SMS API settings. Run the following command:

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twilio api:core:messages:create --from "+1234567890" --to "+9876543210" --body "Hello, World!" --media-url "https://example.com/image.jpg"

This command creates a new MMS message with the specified Media URL and sends it to the designated recipient.

Prevention: How to Stop This Coming Back

To prevent the “MMS Not Sending” error from recurring, follow these best practices:

• Ensure that the Media URL is always publicly accessible and has a valid MIME type.
• Regularly monitor MMS messaging logs for errors and adjust settings as needed.
• Use Twilio’s built-in debugging tools, such as the Twilio Debugger, to identify and resolve issues quickly.

If You Can’t Fix It…

[!WARNING] If Twilio continues to experience issues with MMS messaging, consider switching to Nexmo, which handles Media URLs natively without these errors. However, be aware that switching to a new platform may require significant changes to your existing infrastructure and codebase.

FAQ

Q: Will I lose data fixing this? A: No, fixing the “MMS Not Sending” error should not result in data loss, as it only involves updating settings and verifying Media URLs. However, it’s always a good idea to back up your data before making any changes to your Twilio configuration.

Q: Is this a bug in Twilio? A: The “MMS Not Sending” error is not a bug in Twilio, but rather a configuration issue that can be resolved by following the steps outlined in this guide. Twilio’s documentation and support resources provide detailed information on how to configure MMS messaging and troubleshoot common issues. As of Twilio’s latest version (2026.01), the MMS messaging feature has been updated to include improved error handling and debugging tools.

📚 Continue Learning

Check out our guides on Twilio and MMS Not Sending.