Asterisk Won't Dial Another Asterisk Server Correctly

Asterisk version: 1.01
My situation is the following:

My Asterisk box won’t Dial a specific remote Asterisk server. It dials other servers correctly (and all servers have the same configuration). Other servers can dial this remote server too (so it’s not a firewall problem).

I tried using a Windows program called Firefly to test this. In this program, the URL is dialed correctly, and someone answers at the other side (IAX2/
The same line “exten => 30,1,DialIAX2/” in extensions.conf doesn’t work. The CLI on the server that’s dialing gives me this (IPs, domain names and passwords were changed for the purpose of this posting):

“-- Accepting AUTHENTICATED call from, requested format = 1024, actual format = 1024
– Executing Dial(“IAX2/user@user/5”, “IAX2/”) in new stack
– Called
Aug 9 10:45:30 WARNING[114695]: chan_iax2.c:1473 attempt_transmit: Max retries exceeded to host on IAX2/ (type = 6, subclass = 1, ts=6, seqno=0)
– Hungup ‘IAX2/’
== No one is available to answer at this time
– Timeout on IAX2/user@user/5
== CDR updated on IAX2/user@user/5”

What the CLI with verbose on the other server giving you ? You can may be find a clue there !

Cli with “set verbose 5” on the server yeilds absolutely nothing (ie, it’s not even recieving the connection?)

Well, it’s hard to say with so little information. One more think that can seems obvious but, had you check if the domain name is pointing to the right IP ? I notice that you use dnsalias system, so make sure the IP is update and accurate to the real one.

You can may be also get more clue using CLI command :
iax2 show peers
iax2 show registry

Regards !