Forums Connection Issues Connection problem BUT not with all servers!

I connect to irc.us.rizon.net with no issues.
Yet when I try to connect to irc.eskimo.com in Newnet I get the following error lines:

Local host: nbcarlo (192.168.0.2)
-irc.eskimo.com- *** Looking up your hostname...
-irc.eskimo.com- *** Checking Ident
-irc.eskimo.com- *** Couldn't look up your hostname
-irc.eskimo.com- *** No Ident response
-irc.eskimo.com- *** Banned AGLINE ID c38a0fb9bbab3f0b64d2aed950499a7c -- Remove the underscore in your real name field
Closing Link: 127.0.0.1 (*** Banned )

N.B.: I do not have any underscore in any field (name, nickname, etc.).

After a few reconnection trials I get the following:

Local host: nbcarlo (192.168.0.2)
Closing Link: 127.0.0.1 (*** Banned (cached))
* [10054] Connection reset by peer

After a few further reconnection trials I get this:

Closing Link: 127.0.0.1 (*** Banned (cached))
* [10053] Software caused connection abort.

All the above happen within the same connection session.

My WinXP Firewall is activated, but I do not think it is the culprit, since I connect normally with irc.us.rizon.net .

My details:
WinXP SP2
mIRC 6.21
Netgear router with dynamic IP address.

Thanks,
Carlo