Polycom SPIP randomly going Unreachable


Hoping someone else has had this issue. We have a customer with Polycom SP IP550’s with a FreePBX system hosted in our DC, remote to their site.

Randomly a phone will go Unreachable, using packet capture I can see the PBX is sending OPTIONS every so often to it but I am getting no replies at all. I have remote access to the customers server, so I can get to the web UI of the phone, and if I reboot it I can see it upload logs and download firmware and configuration but never see it attempt registration (or anything SIP).

The phone logs show;
Failed to register User: 1004 Error Code: 480 Temporarily Unavailable

Is it possible at all to get telnet to these phones or run a ping at all? Seems like it’s working, because it can get it’s configs from a web server running on the same box as Asterisk but just no SIP whatsoever… Scratching my head…

Found the config to enable telnet…

   <diags.telnetd diags.telnetd.enabled="1">