We are currently facing an issue with Callers disconnecting from the PSTN and callstate on the IP Phone shows active. The call flow is as below
PSTN-->Cisco 3845--->CUCM 5.1
Signalling between the Voice GW & CUCM is SIP and the configs seem fine. Whenever the caller disconnects we recv Q931 disconnect with cause value 31 (Normal Unspecified) and Sip bye with Q850 reason = 31 sent to the callmanager and CUCM responds back with a 200 ok. On the IP Phone the call stays active for 30 secs and then disconnects.
CUCM ver 18.104.22.16800-2
IOS 12.4 15 T9 on Cisco 3845 platform.
Any idea what could be causing the problem?