So I actually witnesses this behavior on my own extension today.
Call came in at 11:11 which I ignored and caller left voicemail which I never checked. Phone MWI light came on and screen displayed missed call and voicemail icon.
By 12:13 I glanced at my phone and noticed MWI light was off, screen displayed missed call but no longer had the voicemail icon. Logged into FreePBX and could see the new voicemail in my inbox.
At 12:48 phone played the stutter tone when a user has an unchecked voicemail, I looked over but no MWI or screen icon.
At 1:36 head stutter tone again, looked over more quickly and saw the screen displaying 1 new voicemail but then immediately went back to normal wallpaper with no notification.
At 2:37 rebooted phone, MWI came on and voicemail icon displayed.
After an unknown period of time I lost the MWI and voicemail icon again.
So I was curious if during this period of behavior if any extension with a voicemail would behave the same. So I have a test extension on my desk, I called it and left a voicemail. MWI and voicemail icon came on as normal. There was a few updates available, so I updated and reloaded asterisk. Rebooted both phones, and voicemail notifications came on as expected. I left for the day.
At 0900 this morning phones woke up from sleep. My extension is still showing MWI and voicemail icon. The test extension is only showing voicemail icon, the MWI turned off at some point last night.
By 925, test extension also lost the voicemail icon.
Is there a methodology where I can see when the phone makes a request to the server for voicemail info, and to see the response from the server? Obviously it initially works, but then why does it lose it?
I pulled a syslog from the phone, and I can see where it recognizes a voicemail from the server, then seconds later is does not then tells the gui. I will post a snip below.
At this point I don’t know if this is a phone issue, asterisk issue or perhaps a channel driver issue. In trying to eliminate something, I have converted the test extension over to chan_sip. It immediately recognized a new voicemail along with MWI and gui icon. I’m just going to let it sit and see what happens.