It looks like the MSN certificate got expired for pidgin. Please remove the file omega.contacts.msn.com. present under /root/.purple/certificates/x509/tls_peers/ or /home/username/.purple/certificates/x509/tls_peers/ Download the same from http://files.andreineculau.com/projects/pidgin/omega.contacts.msn.com.txt. Once it has been downloaded, move it as omega.contacts.msn.com from omega.contacts.ms
![The certificate for omega.contacts.msn.com could not be validated. The certificate chain presented is invalid.](https://cdn-ak-scissors.b.st-hatena.com/image/square/8d71ff5111e05619a10d29bb40d7aebaa75c8fbc/height=288;version=1;width=512/https%3A%2F%2Fs0.wp.com%2Fi%2Fblank.jpg)