From time to time I have problem with dialing out and noticed a lot of these:
WARNING[4028][C-00005d05] app_dial.c: Unable to create channel of type ‘SIP’ (cause 20 - Subscriber absent)
This is just warning and not error so it should affect my trunk - am I right?
FreePbx is behind firewall with NAT enabled and external IP. Trunk is set as simple as possible:
Cause No. 20 - subscriber absent.
This cause value is used when a mobile station has logged off. Radio contact is not obtained with a mobile station or if a personal telecommunication user is temporarily not addressable at any user-network interface.
for a more diagnostic view , “sip set debug ip (IP Provider)[:port]” and for resolution, ensure your freeepbx_routes/routers/firewall/network/VSP/CID/Codecs are all adequate and in agreement for the call to “get through”