GOautodial Open Source Omni-channel Contact Center Suite

I've this problem:

[Aug 9 19:17:42] Manager 'sendcron' logged on from 127.0.0.1
[Aug 9 19:17:42] -- Executing [8600051@default:1] MeetMe("Local/8600051@default-0000001b;2", "8600051,F") in new stack
[Aug 9 19:17:42] > Channel Local/8600051@default-0000001b;1 was answered.
[Aug 9 19:17:42] -- Executing [390873361010@default:1] AGI("Local/8600051@default-0000001b;1", "agi://127.0.0.1:4577/call_log") in new stack
[Aug 9 19:17:42] Manager 'sendcron' logged off from 127.0.0.1
[Aug 9 19:17:42] -- AGI Script Executing Application: (EXEC) Options: (Set(_CAMPCUST=AGENT))
[Aug 9 19:17:42] -- <Local/8600051@default-0000001b;1>AGI Script agi://127.0.0.1:4577/call_log completed, returning 0
[Aug 9 19:17:42] -- Executing [390873361010@default:2] Dial("Local/8600051@default-0000001b;1", "SIP/0873361010@Costa,,tTo") in new stack
[Aug 9 19:17:42] == Using SIP RTP CoS mark 5
[Aug 9 19:17:42] -- Called SIP/0873361010@Costa
[Aug 9 19:17:42] WARNING³³⁰⁴: chan_sip.c:21126 handle_response_invite: Received response: "Forbidden" from '"M8091917420003965048" <sip:5164536886@62.108.35.127>;tag=as04f30df5'
[Aug 9 19:17:42] Everyone is busy/congested at this time (1:0/0/1)
[Aug 9 19:17:42] -- Executing [390873361010@default:3] Hangup("Local/8600051@default-0000001b;1", "") in new stack
[Aug 9 19:17:42] Spawn extension (default, 390873361010, 3) exited non-zero on 'Local/8600051@default-0000001b;1'
[Aug 9 19:17:42] -- Executing [h@default:1] AGI in new stack
[Aug 9 19:17:42] -- <Local/8600051@default-0000001b;1>AGI Script agi://127.0.0.1:4577/call_log--HVcauses--PRI-----NODEBUG-----21-----CHANUNAVAIL---------- completed, returning 0
[Aug 9 19:17:42] == Spawn extension (default, 8600051, 1) exited non-zero on 'Local/8600051@default-0000001b;2'
[Aug 9 19:17:42] -- Executing [h@default:1] AGI in new stack

My carrier is configured this way:
[Costa]
host=xxxxxxxxx
username=xxxxxx
secret=xxxxxxxx
disallow=all
allow=g729
allow=gsm
allow=ulaw
type=friend
dtmfmode=rfc2833
context=trunkinbound
qualify=yes
insecure=very
nat=yes

go*CLI> sip show peers
Name/username Host Dyn Forcerport ACL Port Status
8001/8001 (Unspecified) D N 0 UNKNOWN
8002/8002 (Unspecified) D N 0 UNKNOWN
8003/8003 (Unspecified) D N 0 UNKNOWN
8004/8004 (Unspecified) D N 0 UNKNOWN
8005/8005 (Unspecified) D N 0 UNKNOWN
8006/8006 (Unspecified) D N 0 UNKNOWN
8007/8007 (Unspecified) D N 0 UNKNOWN
8008/8008 (Unspecified) D N 0 UNKNOWN
8009/8009 (Unspecified) D N 0 UNKNOWN
8010/8010 (Unspecified) D N 0 UNKNOWN
8011/8011 (Unspecified) D N 0 UNKNOWN
8012/8012 (Unspecified) D N 0 UNKNOWN
8013/8013 (Unspecified) D N 0 UNKNOWN
8014/8014 (Unspecified) D N 0 UNKNOWN
8015/8015 (Unspecified) D N 0 UNKNOWN
8016/8016 (Unspecified) D N 0 UNKNOWN
8017/8017 (Unspecified) D N 0 UNKNOWN
8018/8018 82.61.128.135 D N 1026 OK (156 ms)
8019/8019 (Unspecified) D N 0 UNKNOWN
8020/8020 (Unspecified) D N 0 UNKNOWN
8021/8021 (Unspecified) D N 0 UNKNOWN
8022/8022 (Unspecified) D N 0 UNKNOWN
8023/8023 (Unspecified) D N 0 UNKNOWN
8024/8024 (Unspecified) D N 0 UNKNOWN
8025/8025 (Unspecified) D N 0 UNKNOWN
8026/8026 (Unspecified) D N 0 UNKNOWN
8027/8027 (Unspecified) D N 0 UNKNOWN
8028/8028 (Unspecified) D N 0 UNKNOWN
8029/8029 (Unspecified) D N 0 UNKNOWN
8030/8030 (Unspecified) D N 0 UNKNOWN
8031/8031 (Unspecified) D N 0 UNKNOWN
Costa/3906880800 149.202.190.63 N 5060 OK (17 ms)

go*CLI> sip show registry
Host dnsmgr Username Refresh State Reg.Time
sip02.ricaricacredito.net:5060 Y 3906880800 105 Registered Tue, 09 Aug 2016 19:24:34

it seems to me entirely correct, but it does not work!
Where am I wrong?
Thanks for the help