Hello all. I have an issue where outbound calls fail instantly with a ‘busy line’ message on a trunk over which inbound calls work fine. The PBX has another trunk to an SBC and inbound/outbound calls work. I’ve used the same configuration for both, inbound and outbound rules also. Both trunks go over dedicated L2 circuits - no registration involved.
The 20959901 extension belongs to a range allocated to us by the remote party. The 20930315 extension is a valid extension on the remote PBX. Calls from 20930315 to 20959901 are routed and end on my own extension on my PBX correctly (inbound rule works).
On outbound I see a ‘500 Internal Server Error’ message. The vendor of the remote system says that my INVITE is missing the CDPN and should be formatted “sip:user[at]host” as a minimum.
I’m rather new to FreePBX and Asterisk and I have not been able to find a solution. I really hope someone can help.