Due to many reports of outbound calls being denied (Blocked Due To Spam Designation) we wanted to post this statement from our engineering department.
We were able to locate the reported calls and identified that when making test calls from the Original ANI the call yields to SIP 403 but when making test calls from a different ANI over our T-Mobile direct, the call completes to live answer. The term-end appears to be blocking calls from the source. The owner of the phone numbers would need to investigate or remove any blocks due to CPNI regulations. Please let us know if you have any questions or if we may offer any other assistance concerning this matter at this time.
T-Mobile uses a company named First Orion for that information and they are wrong often lately. You can have your number(s) whitelisted by registering them here Call Transparency, Report Improperly Identified Call, www.freecallregistry.com They will do manual check and calls to the numbers to verify and then take away the flag. in the future things like SHAKEN/STIR will keep these false positives from happening, until then this is the process unfortunately. We have also attached the Matrix from Inteliquent on how to report any numbers that are getting flagged for SPAM/fraud.