AWS Toll-Free Number SMS Blocked by Verizon & AT&T — Need Help Escalating Service Issue

Question

Hello AWS Community,

I’m experiencing an issue with an AWS toll-free number registered for SMS messaging. Messages sent through this number are being blocked by Verizon Wireless and AT&T Mobility, with the delivery error:
"Phone carrier has blocked this message".

Side-Note: I'm currently attempting the registration of another TFN and actively working with org leads to get the information together for short-code and 10dlc registrations.

Details:

We are not in the sandbox.

The toll-free number is fully registered, active, and billed through AWS.

The number was able to send messages successfully for about a month until mid-June 2025.

Identical messages sent from another AWS application deliver successfully to the same recipients and carriers.

This issue has persisted for nearly two months despite multiple support contacts. We have been stuck at this stage:

"*Hello

Thank you for your inquiry for Toll Free Number.

We are currently researching the answer to your query with our downstream partners. This process may take 5 days. However, if we need to obtain additional information from you, it might take longer to resolve your request.

Thank you for choosing Amazon Web Services.

We value your feedback. Please share your experience by rating this and other correspondences in the AWS Support Center. You can rate a correspondence by selecting the stars in the top right corner of the correspondence.

Best regards,
Trust and Safety*"

Sample delivery failure log for Verizon:

{
  "phoneCarrier": "Verizon Wireless",
  "smsType": "Transactional",
  "providerResponse": "Phone carrier has blocked this message",
  "status": "FAILURE"
}

I’ve been informed this is a service delivery problem requiring escalation, but AWS support has not yet been able to resolve it.

My questions are:

Are there known carrier-level blocks or reputation issues on AWS toll-free numbers with Verizon or AT&T?

Is additional registration or approval needed specifically for these carriers?

Has anyone successfully escalated this type of problem to the appropriate AWS internal team?

Any advice on next steps or workaround solutions?

Thanks in advance for any guidance or help!

re:Post Agent · Answer

Based on your description, you're experiencing a carrier-level blocking issue with your AWS toll-free number for SMS messaging, specifically with Verizon Wireless and AT&T Mobility.

This type of "Phone carrier has blocked this message" error can occur for several reasons, even when your toll-free number is properly registered and was previously working. Here are some potential causes and solutions:

1. Carrier Filtering: Mobile carriers implement their own filtering mechanisms that can block messages based on content, volume, or other policies. Even with proper registration, carriers may still block messages if they trigger certain filters.

2. Message Content: Review your message content to ensure it complies with carrier guidelines. In one documented case, a simple URL shortener (tinyurl) in the SMS content triggered carrier blocking. Check if your messages contain links, specific keywords, or patterns that might be flagged.

3. Reputation Issues: If your toll-free number has been associated with a high volume of messages or complaints, carriers might have implemented blocks. This can happen even if you've been sending legitimate messages.

4. Opt-out Status: Ensure recipients haven't previously opted out of receiving messages from your number.

While AWS Support is working with their downstream partners, here are some steps you can take:

1. Test with different message content to determine if specific content is triggering the blocks.

2. Monitor your CloudWatch logs for more detailed error messages or delivery statuses.

3. Continue pursuing your alternative options (new TFN, short code, or 10DLC) as these might provide better deliverability.

4. Request that AWS Support specifically check if your toll-free number has been flagged or blocked at the carrier level and if remediation is possible.

5. Consider temporarily using your other AWS application that's successfully delivering messages as a workaround until this issue is resolved.

Unfortunately, carrier-level blocks can be challenging to resolve quickly as they involve coordination between AWS and the mobile carriers. Continue to follow up with AWS Support and emphasize the business impact of this issue to help prioritize the escalation.  
**Sources**  
[SNS SMS Deliverability Issue (TEXT_BLOCKED) Despite 10DLC Registration | AWS re:Post](https://repost.aws/questions/QUaFwoSFh2TN-jqokPoXj7bg/sns-sms-deliverability-issue-text-blocked-despite-10dlc-registration)  
[AWS SNS can not send SMS to mobile phone | AWS re:Post](https://repost.aws/questions/QUVa9lqxT9SeWWTnuZvcrZvQ/aws-sns-can-not-send-sms-to-mobile-phone)  
[Phone has blocked SMS | AWS re:Post](https://repost.aws/questions/QU7NDCsEKmTJ2N9t4xUqKSyA/phone-has-blocked-sms)

AWS Toll-Free Number SMS Blocked by Verizon & AT&T — Need Help Escalating Service Issue

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