I am trying to figure out this problem with no luck. Could you please take a look at the attached debug and config and let me know what am I doing wrong.
We are on CUCM 12.5 with a subscriber and a publisher. All the phones are registered to the subscriber. However, all of a sudden in the middle of the day (randomly at any time) users start getting a fast busy signal while making outbound calls. It doesn't happen on all calls.
The call flow is as follows:
CUCM(SIP Trunk)->CUBE(SIP Trunk)->ITSP
The ITSP doesn't use authentication as we have a direct fibre link to them.
Any help would be greatly appreciated.
Can you please run and share a debug voice ccapi inout with a debug ccsip messages when a call fails? Please let me know Originating number, Destination number and time of the call.
Unfortunately, I have not been able to duplicate the issue since. So the logs I attached were the only ones I was able to capture while we were having the issues. While I'm glad the issue resolved itself, I would still like to get to the bottom of this.
Please check CUCM CDR to get the reason of fast busy.
If you get disconnect reason code from originating side in CDR, i will suggest you to take cucm traces for that specific time to investigate the issue.
If you get disconnect reason from destination side , you can try to replicate the issue and share us debugs to investigate.
Without additional logs, we won't be able to identify what's is happening with those calls. If sometime you are able to replicate, please share the call logs and we can check them.