HI guys, for a 3CX customer we have a problem with incoming calls being dropped after 7 seconds. The anomaly occurs for some calls with a frequency of approximately 1 in 4 calls made. By contacting the incoming number 0456490177 the call is answered regularly by the digital responder which invites you to press the DTMF tones. Approximately one in 4 calls is always answered by the digital answering machine but from the beginning of the call including the answer, after 7 seconds, it is terminated. From the tcpdump, all the actors involved being equal, we can see that for the call that is rejected you never receive a response (200OK) from the 3CX control unit towards the trunk that made the invitation. All things being equal, including the invitations received from 3CX, we do not understand the reason why 3CX does not respond to the call rejected with the 200OK. What is missing in the invite compared to a call that works regularly? can you kindly help us analyze these tracks? in front of the switchboard there is an audio code SBC managed by us. I would add that currently the problem arises if the call passes through the CFD which in turn forwards to the digital responder. In fact, by bypassing the CDF and rerouting the incoming call directly to the digital responder, all calls are successful. The CDF project has also been redone several times without success, also because in fact the call arrives at the 3CX exchange. Can anyone help me with this? Thanks a lot!!
CALL OK:
CALL KO:
CALL OK:
CALL KO:
