UCM6104 IVR randomly will not work


Hey Folks,

I have ucm6104 ip pbx. When someone calls to analog line , green light blinks on ucm ip box but the call is not answer by IVR randomly.

Most of time IVR answers the call but randomly IVR will not kick in and the call goes on ringing.
This happens especially it there is a immediate new inbound call after last call is ended.

Please see attached screenshots for setting for analog trunk, inbound rules and IVR settings.

Please help to fix this issue.

Thank you very much.