Hello!
I am using freepbx version 15. We configured a ring group that contains a mobile number (so an external number). My provider requires to get a known number as Caller ID for outbound call. I so configured the option “Change External CID Configuration” to “fixed CID value” and fill the correct phone number. But it does not work. I got the message: " Everyone is busy/congested at this time" / “Local/{called number}@from-internal-000000e0;1 is circuit-busy” .
Checking the log, I can see that the Caller ID is not the one I have set but the original caller ID (the number of the person who called the ring group).
The trustrpid and sendrpid are set to “yes” (in the trunk configuration).
The mobile number added in the ring group has the # sign at the end.
Any suggestion would be appreciated 
Thx!