It goes like this: When comodo asked me, to allow or deny acces for MSN messenger, Imade a mistake and pressed deny. I also pressed remember. Before this, I already had MSN as an exception, so it worked. It looks that I blocked a port and now MSN cant sign in.
In application monitor MSN messenger should be listed as an entry.
Remove it and reload, when prompted set your answer to allow.
This should cure your fault.