I normally use Pidgin (2.6.4 and now 2.6.5) on Ubuntu to connect to jabber.org via XMPP for instant messaging. Yesterday, sometimes when I tried to connect, I would get the following error:
Unable to validate certificate The certificate for jabber.org could not be validated. The certificate chain presented is invalid.
I have no idea why this is happening; other people in the same office are having no problem connecting to jabber.org, and today it's happening every time. I tried removing the certificate for jabber.org (in ~/.purple/certificates/x509/tls_peers/jabber.org), and restarting Pidgin a few times, but no dice. I've tried every combination of settings I can think of (turning off TLS/SSL, allowing unencrypted streams, etc.) but nothing works. Any ideas?