Asterisk stopped on the first step auth

I want to move asterisk to the new server. From 1.8.11-cert7 to For this i had make dump on old server and restore it on new server. Therefore all settings on both server is identical.

There are two steps to registry the trunk in asterisk on voip-provider:

  1. Asterisk send registry-request, and get 401 Unauthorized
  2. Asterisk send registry-request with md5 hashed password, and get 200 OK

As follows from this is realy happening in the old server.

But when i try to registry this trunk with same settings from new server, then authentication failed on first step.

As follows from
Asterisk send registry-request, get 401 Unauthorized, and send same initial registry request again in infinite loop.

Why they do it and how to fix it?

P.S. There are new server into DMZ. But I do not think that this is a reason.

as i remember, registration of beeline trunks involves the edition of /etc/hosts file, changing ip address for some of their domain names.
and if you are in dmz now, try to comment out localnet/externaddr lines in sip.conf and change nat=yes to nat=no.