US Carrier Call Blocking

Telnyx has become aware that major carriers in the US industry are actively flagging/blocking calls to their subscribers devices due to them deeming the calls as potentially fraudulent, where end users may see "Fraud Risk", "Spam Risk", "Potential Spam", "Robocaller", "Scam Likely" and other names which their carriers are prepending onto your caller IDs.

We are seeing, that high volume calls from non-rotated caller IDs are experiencing a higher amount of user busy responses in the form of a SIP 480/486 Busy Here.

In some cases, it's also being reported that the carriers of the destinations are using services that are categorizing calls as "Potential Spam" on the user's devices.

What to do

We also understand that there are many valid & legitimate use cases, where there is a necessity for high volume calls (e.g. alerts, appointment reminders, etc.) Providers and their analytics partners have established mechanisms for callers to seek redress to fix any inadvertent call labeling or blocking concerns, as well as to register their numbers in the first instance.

The first step is to register with the Free Caller Registry. Several carriers use that to pull company information for phone numbers so having your numbers registered here will help lower the chances of terminating carriers flagging your numbers for spam.

Next step is to push to the specific carrier that is flagging your calls. This page has a very complete set of contact information or forms to submit to each different terminating carrier.


We are committed to combating spoofing and illegal robocalling through implementing the industry-wide STIR/SHAKEN solution, in an effort to play our part in reducing these illegal occurrences. You can read more about our three-part articles where we discuss the implementation in detail.

Google Verified Calls

We also have a new product that can help out with this specific situation, it's Verified by Google. This helps you brand your calls on android mobile phones and add a verified tag when calling them. You can read more about it here

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