I can't connect to Undernet...
I get this message:

[2] AUTO Proxied Gline.
-
Closing Link: Apsu by Diemen.NL.EU.Undernet.org (K-lined)

it's always the same , no matter what servwe I try to connect to. What do you think I should do?

That means you have a proxy server, running on the same IP address the server sees you coming from.

check their website, like this part: here

tx for helping me!

you're welcome