If a message you sent is not delivered to the end device and returns a 30006 error code, this means that delivery of your message failed due to the destination being a landline and incapable of receiving SMS, or an unreachable destination carrier.
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:
- Verify the destination (to) number is not a landline number with the Lookups API.
- Check the Twilio Status Page to see if an active incident could be causing your issues.
- 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?
Continued Error 30006 Issues
If you can rule out all of the above 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 30006, and Open a support request.