If a message you sent is not delivered to the end device and returns a 30007 error code, this means that your message was filtered out due to a carrier violation.
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, it's likely your repeated Error 30007 results are being caused by carrier filtering. The rules for carrier filtering can vary throughout the industry, making it difficult at times to pin-down exactly why a message is being filtered out. For more details, including potential workarounds, please see our article How Does Carrier Filtering Work?