Amazon Simple Notification Service Error

This error message indicates that your AWS account doesn't have the necessary permissions or subscription to access the SMS features in Amazon SNS. The specific error "OptInRequired" (Status Code: 403) suggests that your AWS access key ID needs a subscription for the service.

Here are steps you can take to resolve this issue:

1. Verify that you have opted in to use the SMS service. AWS requires explicit opt-in for SMS messaging capabilities.

2. Check if your account is in the SMS sandbox environment. New AWS accounts are placed in a sandbox environment with limitations until you request production access.

3. Ensure you have the appropriate permissions in your IAM policy to access the End User Messaging service, Amazon SNS, and Amazon Pinpoint.

4. If you've recently acquired an origination identity (phone number or sender ID) through the End User Messaging service, you need to explicitly provide permissions for SNS to use these identities. This requires updating the resource policy for your origination identity.

5. Verify that you're using the correct AWS region that supports SMS messaging for your intended destination country.

6. If you've checked all the above and still encounter issues, consider opening a support ticket with AWS for further assistance.

The error specifically mentions PinpointSmsVoiceV2, which suggests that the issue might be related to permissions between SNS and the newer End User Messaging service that manages origination identities.
Sources
Common Errors - Amazon Simple Notification Service
"The provided number does not exist or does not belong to the account." error when trying to send messages via SNS or Pinpoint even though the required origination identity is acquired in the account. | AWS re:Post
"NO_ORIGINATION_IDENTITIES_FOUND" error when trying to send messages via SNS or Pinpoint even though the required origination identity is acquired in the account. | AWS re:Post