One of our customers has a (relatively) new issue when forwarding calls.
The user dial *72 to forward his calls to his cell phone. The Call Forward Ring Time is set at 30 seconds (default), so in theory, the cell phone should ring for about 30 seconds and the call should then be redirected to the voicemail on the FreePBX. What happens is that the call hangs up after around 25 seconds. Just a quick beep and the line drops.
If I set the Call Forward Ring Time to 20 seconds, it works fine, the call gets redirected to the voicemail on the FreePBX after 20 seconds.
It seems like there is some kind of timeout over the 20 seconds mark. In the logs, it looks just like a regular hangup. I didn’t test this scenario on another system but I will do it soon.
Does anyone have on clue on what’s going on ?
The system is using chan_sip
Some settings I’ve tried but didn’t work:
In the General SIP Settings, change the RTP timeout to a higher value (120 seconds)
Change the default ring time in the Advanced settings to a higher value (40 seconds)