SNS sandbox testing using multiple phone numbers

The error you're encountering is related to the limitations of the AWS SNS sandbox environment and the availability of origination identities for different regions. Here's what's happening:

1. In the SNS sandbox, you can only send messages to verified destination phone numbers.

2. You've successfully added and verified an Indian phone number, which is good.

3. When trying to add a UK mobile number, you're receiving an error because there's no available origination identity to send the verification message to that number.

4. The error message "No origination entities available to send" suggests that in your selected region (eu-west-1), there isn't an origination identity (like a phone number or sender ID) that can send messages to UK numbers.

5. It's important to note that origination identities can only send messages within their country or region. For example, an origination identity for the United States can only send verification messages to destination phone numbers in the United States.

To resolve this issue, you have a few options:

1. Check if you have an active origination identity in your account that has text or voice message capabilities for the UK region.

2. If you don't have an appropriate origination identity, you may need to acquire one that can send messages to UK numbers.

3. Alternatively, you could use simulator phone numbers for testing. AWS provides Origination simulator phone numbers and Destination simulator phone numbers that can be used to test sending and receiving messages without the need for actual phone numbers.

4. If you specifically need to test with real UK numbers, you might need to contact AWS support to ensure you have the necessary permissions and origination identities set up for your account in the eu-west-1 region.

Remember, you can add up to 10 verified destination numbers in the sandbox environment. If you're having trouble with specific regions, it might be worth considering using simulator numbers or focusing on regions where you have confirmed origination identities available.
Sources
Add a destination phone number while in the AWS End User Messaging SMS sandbox - AWS End User Messaging SMS
CreateVerifiedDestinationNumber - Amazon Pinpoint SMS and Voice v2 API
create-verified-destination-number — AWS CLI 2.22.4 Command Reference