If a message you sent is not delivered to the end device and returns a 30003 error code, this means that delivery of your message failed due to an unavailable or unreachable destination. Common examples are a user who is outside of cellular service or whose mobile device is powered off.

In some cases, a delivery error may occur once due to a transient issue downstream of Twilio. To test whether the issue occurs again, please attempt to send another message to the user via a REST API request.

If you see similar results, continue troubleshooting with the following checklist:

• 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?

If you can rule out all of the above issues, continue troubleshooting below.

Repeated 30003 Errors

Repeated error 30003 results on undelivered messages sent from messages in the US could be caused by the destination user having a wireless plan that does not support "Premium" messages (i.e. A2P traffic). Recipients may need to contact their wireless provider to confirm their plan supports this type of traffic. 

Repeated error 30003 results on undelivered messages sent from long codes (regular phone numbers) could also be caused by carrier filtering, particularly in the US and Canada.

Twilio displays filtered messages with error 30007 whenever possible, however in some cases we may receive an ambiguous error code from the carrier on filtered messages. For more details, including potential workarounds, please see our article How Does Carrier Filtering Work?

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 30003, and Open a support request.