The Carrier Rejected Error occurs when outbound AI calls fail due to the recipient's carrier blocking the number—often because it's flagged as spam or hasn't been properly registered. This guide helps you diagnose, prevent, and resolve this issue to ensure your outbound calls go through successfully.
Tip*: Before purchasing Twilio numbers test them in using this tool: https://spamlikely.io/bulk-tester
Q: What does “Carrier Rejected” mean?
A: It means the recipient's phone carrier has blocked the call before it could connect—usually because the number is flagged as spam or hasn't met carrier requirements.
Q: How can I test if a Twilio number is likely to be rejected?
A: Before purchasing or using a number, test it using:
https://spamlikely.io/bulk-tester
This checks spam scores and likelihood of rejection across multiple carriers.
Q: What’s the best way to avoid this error?
A:
Use new, clean numbers tested with the spam tester above
Avoid rotating through too many numbers (which looks spammy)
Register your number with CNAM and major carriers (A2P 10DLC registration)
Q: What should I do if I’m already getting this error?
A:
Stop using the flagged number
Run it through the spam test tool
Swap it for a clean tested number
Implement proper call tagging and compliance registration with Twilio CNAM & SHAKE & STIR
Q: Can I automate number pools if one number is rejected?
A: Yes, you can set up number pools in the Centerfy Dashboard
Q: Do you have a prebuilt workflow to fix this?
A: Yes! Use our Compliant Outbound Calling Carrier rejection fix, which is setup to automatically call during compliant hours, rotate number pools, and sufficient dial attempts if the dial fails or is unanswered
