Thank you for helping. Sure:

#!/usr/bin/perl -w
use Net::SSH2;
 
my $ssh2 = Net::SSH2->new();
$ssh2->connect('158.226.63.99')
    or $ssh2->die_with_error;
$ssh2->auth_agent('z004kapc')
    or $ssh2->die_with_error;
my $chan = $ssh2->channel()
  or $ssh2->die_with_error;
$chan->exec('pwd')
  or $ssh2->die_with_error;
print while <$chan>;
[download]

And line 7 is the line where you try to talk to the agent. I presume that the environment variables are set up so that the domain socket etc. are found?

Does the error message change when you set the environment variables ($ENV{SSH_AUTH_SOCKET} ?) to some invalid value before creating $ssh2?

Does your Perl process run as the same user as the ssh process you're using to connect?

Maybe consider setting trace => -1 in the constructor to dump lots (and lots) of information, and maybe compare that to what the ssh -vvv executable does. Maybe there is a difference that shows up?

my $ssh2 = Net::SSH2->new(trace => -1);
[download]

This is very helpful, since I don't have this env. Variable for some reason.

I think a cause for this could be that I use Windows, since I need to develop it for windows.

Do you know, how I could make it compatible nevertheless?

Edit: I noticed that it may come across sarcastic, but it is actually helpful, because it made me find out I don't have it