Solved 3CX using Thinktel SIP Trunking - Incoming fails with a 403

[John R]

We're using a 3CX v15.5 system, and I've configured Thinktel SIP trunks as per the guidelines published by 3CX. My outgoing trunks work as expected, but I receive 403 errors on the incoming trunks. The Firewall Test ran clean.

Anyone have similar challenges with this combination? Any recommendations on next steps?

Cheers

 

[John R]

Just discovered the Thinktel IP had been black-listed by my 3CX ....... removed the IP and all works fine.

 

[YiannisH_3CX]

Glad to see the issue in resolved and thank you for sharing your solution