Strange FreePBX Behaviour


We rolled out FreePBX Asterisk to about 80 Cisco phones(7961g and 7945g) yesterday evening. The phones were reset using reset key # and tested by making an extension to extension call, call to external source and call from external source and everything appeared to work fine.

However at some point this morning the system seems to have failed, looking through the asterisk log we found this error when trying to place a call.
[2012-04-26 09:33:34] VERBOSE[6625] pbx.c: – Executing [[email protected]:42] Dial(“SIP/cg08p-00000038”, “SIP/305,15,rtTwW”) in new stack
[2012-04-26 09:33:34] WARNING[6625] app_dial.c:2218 dial_exec_full: Unable to create channel of type ‘SIP’ (cause 20 – Unknown)

No calls where going in or out.

Since then we changed the IP address of the server but this time performed a firmware update on a few phones to test and once again it seems to be working without a problem. We are using a SIP connection via a router.

Has anyone got any insight on what might have happened or why it stopped working?


It would appear your phones lost registration. Next time do a sip show peers and see if the extension is registered. That error happens usually when the phone is no longer registered in Asterisk

thanks Tony,
I will try this and see.


Just looking for your opinion on this Tony, the old system we had running was Trixbox 2.6 on a virtual machine, we brought that one down when we rolled out FreePBX yesterday but it automatically stated up again because of some backup script and was using the same IP address as the FreePBX system.

We brought down the trixbox one again and restarted the freepbx system but dont remember if we restarted freepbx system before taking the trixbox one offline.

Could it be that because the two systems had the same ip address it was causing confusion and thus giving the error seen above.


YEP. Duplicate IP addresses would cause all sorts of problems.