[Asterisk-Users] How do I diagnose the problem in this Asterisk test session with FWD?

[Flash Love]

=============
SJphone Log
============
Outgoing SIP session
Respondent:   (sip:8612 at 192.168.2.2)
Remote client:
Started:  May 26 16:33
Accepted:  no
Ended:  May 26 16:34
End reason:  Call rejected: 503 Service Unavailable

===============
Asterisk Debug
================
Executing Dial("SIP/2201-a83e", "IAX2/<FWDNUMBER>:@iax2.fwdnet.net/612|60|r") 
in new stack
    -- Called <FWDNUMBER>:@iax2.fwdnet.net/612
Tx-Frame Retry[000] -- OSeqno: 000 ISeqno: 000 Type: IAX     Subclass: NEW
   Timestamp: 00014ms  SCall: 00003  DCall: 00000 [65.39.205.121:4569]
   VERSION         : 2
   CALLED NUMBER   : 612
   CALLING NAME    : MyName
   LANGUAGE        : en
   USERNAME        : <FWDNUMBER>
   FORMAT          : 4
   CAPABILITY      : 63494
   ADSICPE         : 2
   DATE TIME       : 179995695

Tx-Frame Retry[001] -- OSeqno: 000 ISeqno: 000 Type: IAX     Subclass: REGREQ
   Timestamp: 00019ms  SCall: 00001  DCall: 00000 [65.39.205.121:4569]
   USERNAME        : <FWDNUMBER>
   REFRESH         : 60

Tx-Frame Retry[001] -- OSeqno: 000 ISeqno: 000 Type: IAX     Subclass: NEW
   Timestamp: 00014ms  SCall: 00003  DCall: 00000 [65.39.205.121:4569]
   VERSION         : 2
   CALLED NUMBER   : 612
   CALLING NAME    : MyName
   LANGUAGE        : en
   USERNAME        : <FWDNUMBER>
   FORMAT          : 4
   CAPABILITY      : 63494
   ADSICPE         : 2
   DATE TIME       : 179995695

Tx-Frame Retry[000] -- OSeqno: 001 ISeqno: 000 Type: IAX     Subclass: LAGRQ
   Timestamp: 10019ms  SCall: 00001  DCall: 00000 [65.39.205.121:4569]
Tx-Frame Retry[000] -- OSeqno: 001 ISeqno: 000 Type: IAX     Subclass: LAGRQ
   Timestamp: 10006ms  SCall: 00003  DCall: 00000 [65.39.205.121:4569]
Tx-Frame Retry[001] -- OSeqno: 001 ISeqno: 000 Type: IAX     Subclass: LAGRQ
   Timestamp: 10019ms  SCall: 00001  DCall: 00000 [65.39.205.121:4569]
Tx-Frame Retry[002] -- OSeqno: 000 ISeqno: 000 Type: IAX     Subclass: REGREQ
   Timestamp: 00019ms  SCall: 00001  DCall: 00000 [65.39.205.121:4569]
   USERNAME        : <FWDNUMBER>
   REFRESH         : 60

=================
IAX CONF
================
register => <FWDNUMBER>:FWDPASSWD at iax2.fwdnet.net

[iaxfwd]
type=user
auth=rsa
inkeys=freeworlddialup
disallow=all
context=fromiaxfwd
context=fwd-out

================
EXTENSIONS CONF
================
FWDUSERID1=<FWDNUMBER> ; your calling number
FWDCIDNAME="MyName"; your caller id
FWDPASSWORD=secret ; your password
FWDRINGS=sip/2201 ; the phone to ring
FWDVMBOX=2201 ; the VM box for this user
FWDPREFIX=8

[inbound-fwd]
include => daytime-fwd|9:00-21:00|*|*
include => nighttime-fwd|21:00-9:00|*|*

;
; Outbound
;

[fwd-out]
exten => _8.,1,SetCallerID(${FWDCIDNAME})
exten => _8.,2,Dial(IAX2/${FWDUSERID1}:
${FWDPASSWORD}@iax2.fwdnet.net/${EXTEN:1},60,r)
exten => _8.,3,Congestion
exten => _8.,4,Macro(fastbusy)
exten => _8.,5,Hangup

[fromiaxfwd]
exten => ${FWDUSERID1},1,Goto(inbound-fwd,s,1)
exten => ${FWDUSERID1},2,Voicemail2,u${FWDVMBOX}
exten => ${FWDUSERID1},102,Voicemail2,b${FWDVMBOX}
exten => ${FWDUSERID1},3,Hangup

[dialout]
include => fwd-out
include => fromiaxfwd

Thanks