I have had this really irritating error come about in the last week where I can't sign in to messenger. Error 81000306 indicates that the problem could be caused by a firewall, proxy settings, DNS cache. I followed all Microsoft's instructions but to no avail and I have ALLOWED msnmsgr.exe in ZoneAlarm, so the lack of info they're giving me is getting on my nerves. I even uninstalled, ran Registry cleaner and reinstalled but still nothing. Can anyone help?