Solved: SIP Cause error Reason: Q.850;cause=38

Wonxie · ‎03-02-2023

Hi

i am trying to establish a trunk with an ITSP using cisco router. however call is not going through and giving below error code.

Reason: Q.850;cause=38

please see a sample sip capture form the router where it recived call from cucm and after matching proper inbound and outbound sip dial peer it sent to itsp using proper bind interface which itsp has whitelisted.

Robert Profit · ‎03-03-2023

Dial-peers can be used for inbound and outbound, although I personally don't like doing it that way for troubleshooting purposes. I believe the dial-peer is creating a problem because it is trying to bind sip from the inside/inbound call leg to that (I am assuming) outside interface 0/0.10, even though it received it from your CUCM on the gi0/1 (10.65.12.3) interface.

So when CUBE attempts to create the session it may not have reachability from that outside interface, where the media is now bound on that call leg, to your inside network/subnet, just one example.

Additionally, just because the 'distant end' (DT) can call you, doesn't mean you can call them.

I would test again after that modification of your dial-peer.
V/R,
Rob Profit

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