Cross‑account usability of existing EUM SMS Resources in Dev account

The DESTINATION_PHONE_NUMBER_NOT_VERIFIED error means the destination number you’re trying to send to must be verified in the account/region making the SendTextMessage call (your Prod account in GovCloud). This is a destination-verification / sandbox-style restriction, not a 10DLC carrier-approval problem.

Cross-account sharing of an existing 10DLC originator/phone pool does not bypass the sending account’s destination-verification restrictions. Your 10DLC can be Active and correctly shared, but Prod will still fail when sending to an unverified destination.

To resolve:

1. For testing, verify the destination phone number in the Prod account/region and retry: https://docs.aws.amazon.com/sms-voice/latest/userguide/verify-destination-phone-number.html

2. For production sending to arbitrary destinations, open an AWS Support case to move the Prod account/region to production access (remove sandbox/destination-verification restrictions). The same documentation covers the sandbox/production workflow: https://docs.aws.amazon.com/sms-voice/latest/userguide/verify-destination-phone-number.html

Cross-account reference: https://docs.aws.amazon.com/sms-voice/latest/userguide/registrations-10dlc-configure-cross-account-access.html