If a message you sent is not delivered to the end device and returns a 30004 error code, this means that delivery of your message failed because the destination is blocked from receiving this message.
The first step to troubleshooting this issue is to attempt to replicate the problems. Attempt to send another test message to this user via a REST API request, or through the API Explorer in Console. If you see similar results, continue troubleshooting with the following checklist:
- Is the destination device powered on?
- Does the device have sufficient signal? If not power the device off, wait 30 seconds, and then power it back up.
- Is the device connected to the home carrier's network? We cannot guarantee message delivery on devices roaming off-network.
- Can the device receive non-Twilio SMS?
- Can the device receive messages from another Twilio number (non-Alphanumeric Sender ID), or with a shorter one-segment (non-concatenated) body?
- Can other devices using the same mobile carrier receive your messages?
If you can rule out all of the above issues, continue troubleshooting below.
"Undelivered" Messages Sent to India
Error 30004 results on undelivered messages sent to India could be caused by the destination number being listed on the national Do Not Call registry. For more information on sending messages to India, including links to update DNC settings, please see our article Limitations for Sending SMS to India.
Repeated Messages with a Failed status and error 30004 results indicate Twilio may be filtering some of your messages internally. This filtering is in place to help protect our customers, and the rules attempt to match what we have observed from the industry. For more details, including potential workarounds, please see our article How Does Carrier Filtering Work?
Continued Error 30004 Issues
Twilio's Support team can help investigate what went wrong with delivering your message. Please collect 3 or more message SIDs in your SMS logs from the last 24 hours that were flagged with Error 30004, and Open a support request.