GOautodial Open Source Omni-channel Contact Center Suite

the details of your setup?

Yes. but with this I understood now all the more fun.
Using SIP RTP CoS mark 5
[Oct 11 15:02:38] -- Executing [89038671133@default:1] AGI in new stack
[Oct 11 15:02:38] -- <SIP/8001-0000000c>AGI Script agi://127.0.0.1:4577/call_log completed, returning 0
[Oct 11 15:02:38] -- Executing [89038671133@default:2] Dial("SIP/8001-0000000c", "SIP/@123,,tTo") in new stack
[Oct 11 15:02:38] == Using SIP RTP CoS mark 5
[Oct 11 15:02:38] -- Called SIP/@123
[Oct 11 15:02:38] WARNING⁶⁴²⁸: chan_sip.c:21126 handle_response_invite: Received response: "Forbidden" from '"8001" <sip:0000000000@192.168.1.16>;tag=as34c6245f'
[Oct 11 15:02:38] Everyone is busy/congested at this time (1:0/0/1)
[Oct 11 15:02:38] -- Executing [89038671133@default:3] Hangup("SIP/8001-0000000c", "") in new stack
[Oct 11 15:02:38] Spawn extension (default, 89038671133, 3) exited non-zero on 'SIP/8001-0000000c'
[Oct 11 15:02:38] -- Executing [h@default:1] AGI in new stack
[Oct 11 15:02:38] -- <SIP/8001-0000000c>AGI Script agi://127.0.0.1:4577/call_log--HVcauses--PRI-----NODEBUG-----21-----CHANUNAVAIL---------- completed,

I'm just confused.

post your sip settings and diaplan used

look like dialplan wrong

in your current dialplan change SIP/@123 to SIP/123/$${EXTEN}

Regards
striker
www.striker24x7.blogspot.com