If you see error 80048820 when you try to sign in to Messenger, try the following steps:

  1. Make sure your PC's date and time settings are correct
  2. Set Internet Explorer security settings to use SSL
  3. Re-register the security.dll files
  4. Scan your PC for viruses
  5. Check your firewall and router settings to make sure that your firewall isn't blocking port 443
  6. Clear the Messenger proxy settings
  7. Reset the proxy server settings for Internet Explorer
  8. Disconnect or bypass your router to make sure your router settings aren't blocking your connection to Messenger
  9. Make sure Internet Explorer isn't set to work offline
  10. Check and clear the entries in the Hosts file
  11. Clear the DNS cache

read how to do each of these for Windows 7, Widows Vista  and Windows XP Messenger sign-in error 80048820 

Get more help for Messenger

Rob