problem with pidgin

[Mark Doliner]

I'm able to login to that XMPP server with no certificate problems.
Pidgin happily accepts the certificate without asking me any
questions. I tested with Pidgin compiled to use both GnuTLS and
libnss. I'm using the CA certificates that are shipped with Pidgin.

My only guess is that your build of Pidgin is configured to use a
system-wide directory containing CA certificates and that the
directory does not contain the CA certificate needed to verify
jabbim.cz.

What error message does Pidgin show to you? What operating system are
you using? Are all of your packages up to date?