How to Fix sign-in error 80004005 for Windows Live Messenger

If you are encountering this error when signing in, please install the latest version of Windows Live Messenger from http://get.live.com/messenger/overview
After installation, verify that you have the version 8.0.0812. If you are still experiencing the issue, pelase contact Messenger Support at http://support.live.com and choose Windows Live Messenger

Updated (16.11.2006):

"Signing in to .NET Messenger Service failed because the service is temporarily unavailable. Please try again later 0x80004005"

CAUSE:
The Microsoft .NET Passport account is blocked by the .NET Messenger Service because the computer may be running a third-party (non-Microsoft) program that is not licensed by Microsoft. This is a violation of the MSN Messenger Terms of Use. This error was originally created by MSN Messenger maintanence procedures. They were probably interested in stopping people from using third party add-on's thay may have a detrimental affect on their service.

To fix the issue you have to request that your email address be unblocked from MSN Messenger. This is a one time deal and you can only be un-blocked from the messenger service once so make sure that you have removed any offending software add-on's before asking

You can either contact msn if you have a paying msn account 1-800-635-7019 or go to http://messenger.msn.com/Help/ContactUs.aspx for non paying customers and request that the account be unblocked.