I'm pretty new to CUCM and SIP, so please go easy on me.
I'm having some difficulty with Outbound calls, in that I get a SIP 404 Not Found error from CUCM after the invite request. Inbound calls are working fine so I'm pretty confident it's something in my set up causing the issue rather than it being at the ITSP end. The basic set up is:
CUCM > Sip Trunk > VG202 > ITSP
ITSP > VG202 > SIP Trunk > CUCM
I've attached the configuration I'm using, sans the sensitive info, and also the debug output of ccsip messages and voice ccapi inout.
If anyone can help me understand where the problem lies and where I should be looking to fix it, I'd really appreciate it.
Your ITSP is not sending (or your VG is not receiving) any response to your INVITEs. You should check with your ITSP if they are receiving the correct SDP headers on their end.