If you use Pidgin as an MSN instant messenger you might have recently started to get the “omega.contacts.msn.com could not be validated. The certificate chain presented is invalid” error. It seems that MSN certificate has expired for Pidgin; so a new certificate needs to be imported into Pidgin for it to work.  There are a few different ways to get the new certificate, the following outlines a couple solutions that i have found to work.

Option #1 – Delete the current certificate and let Pidgin import the new one automatically

1. From within Pidgin,  navigate to Tools > Certificate
2. In the list of certificates, find the omega.contacts.msn.com certificate and Delete it
3. Quit and Restart Pidgin
4. Pidgin should import the new certificate automatically and you should now be able to login.  If not, follow the steps in Option #2 to download and import the certificate manually.

Option #2 – Delete the current certificate and download/import the certificate manually

1. Download the following file  – http://files.andreineculau.com/projects/pidgin/omega.contacts.msn.com.txt
2. Remote the .txt extention at the end of the file name so you end up with omega.contacts.msn.com
3. From within Pidgin,  navigate to Tools > Certificate
4. In the list of certificates, find the omega.contacts.msn.com certificate and Delete it
5. Now click the Add button to import the certificate you just downloaded, Navigate to the omega.contacts.msn.com file
6. Quit and Restart Pidgin
7. You should now be able to login