I was the person in the IRC room yesterday which brought up this subject. Appearantly Microsoft is addressing this problem. I have had the same problem again today, but this time it's different, I couldn't send any messages to my contacts, I couldn't check my email, I know it's not Plus! causing the problem, but the error message that showed up this time is Buffer overflow.....application had to be shut down in order for me to continue.
Hopefully It gets fixed soon, because I don't want to keep using Windows messenger...it's just not the same.