What does “carrier deemed destination number as invalid” mean?

Last updated: November 5, 2026

This error means the recipient carrier rejected the message because it considered the destination number invalid.

What to check

  1. Confirm the phone number is correct.

  2. Check that the number includes the correct country code if needed.

  3. Ask the contact to confirm that their phone is active and can receive messages.

  4. If the number recently worked, ask whether the contact blocked the sending number or changed carriers.

  5. If the issue affects many contacts, escalate to Whippy Support for delivery review.

Common causes

  • The number is disconnected or no longer in service.

  • The contact’s mobile plan is inactive or suspended.

  • The contact blocked the sending number.

  • The number is formatted incorrectly.

  • The carrier rejected delivery before the message reached the device.

Troubleshooting

  • If only one contact is affected, verify the recipient number with the contact.

  • If many contacts are affected, check for carrier or routing issues.

  • If the issue is intermittent, try another communication channel and monitor future sends.