I’m fairly sure this is either a misconfiguration in the user setup, or a limitation in FreePBX, and not a problem with the phone. When I press the Voicemail REST button, I get a fairly generic error “File Layout Error!” which just means the phone didn’t get what it was expecting.
If I enter “http://address.for.pbx:88/applications.php/voicemail/main?user=4248” I get seemingly no response. Other REST apps (such as conference and parking lot) are working, so I don’t suspect it is a problem with the REST server.
Our setup involves virtual extensions, so I suspect that maybe it’s because extension 4248 doesn’t have voicemail set up on it. The actual voicemail is 248, so if I enter “http://address.for.pbx:88/applications.php/voicemail/main?user=248” in a browser, I get a response back. We have the hard phones set up as forwarded extensions because users have multiple phones.
Ideally, we would like to be able to user the Voicemail REST app so that users can check the status of voicemail messages for other mailboxes. I could put in a feature request, but that seems like a pretty big overhaul on the application. Is that something that might be considered as a future enhancement?