Direct Routing Outbound Calls failing

Occasional Contributor



Inbound calls are working fine with my SBC. But for Outbound calls what happens is the my destination mobile rings I answer but the 200OK that is sent back to MS Teams SBC does not come back with an ACK.


Can you please confirm for these calls does the 200 OK sent back to MS Teams SBC need to have the contact header set as Or is the Route of my provider SBC causing an issue ?




dstport: 5061
SIP/2.0 200 OK
Session-Expires: 3600;refresher=uas
Require: timer
Via: SIP/2.0/TLS;branch=z9hG4bK4562c25
Record-Route: <sip:;lr=on> -- My Core network SBC
Record-Route: <;transport=tls;r2=on;lr> --My Teams SBC
Record-Route: <sip:;r2=on;lr> -- My Teams SBC
Record-Route: <;transport=tls;lr>
To: <;user=phone>;tag=3806077363-1364677916
From: <;user=phone>;tag=7d4ad29020844e15a6b9296114776767
P-Asserted-Identity: <sip:+447825312603@>
Call-ID: ef7a2d7c8ce353658bfb0c5956f5b527
Contact: <sip:+447825312603@>
Content-Type: application/sdp
Accept: application/sdp
Content-Length: 578




2 Replies

Simple answer = yes @VoipGuyUK 



To clarify for others that might stumble on your self answer, I'm sure you meant the Contact Header must have <>.  You'd asked two questions ;)