This morning I tried Pidgin and got an error message saying:
"Unable to validate certificate. The certificate for omega.contacts.msn.com could not be validated."
For the record, the problem isn't on Pidgin's end – it's a misconfiguration of the MSN servers. Here is a short term fix until the problem on Microsoft's end is fixed.
How to replace your certificate (the GUI method)
Go to pidgin's Tools->Certificates. Remove the old certificate. Don't close this window yet. (You can, but it is easier to not).
With your browser, go to https://omega.contacts.msn.com. It will give you "Directory Listing Denied"error.
With Firefox, click on the lock symbol in the lower right corner. This will display dialog box about the page info. Click the button "View Certificate." On the window that pops up, go to the Details tab. Click on the "Export" button to export the certificate to a file.Call it whatever you like.
Now, go back to the pidgin Tools->Certificates dialog. Click the "Add" button to add the newly exported certificate. I had to specify the hostname as explicitly: omega.contacts.msn.com
This was the only way I could get it to work.