解決Windows Live Messenger 無法登入, 錯誤碼81000306

Possible fixes:

1. Check Internet connection
   Link status, proxy setting, firewall, etc.
2. Flush DNS
   cmd# ipconfig /flushdns
3. Disable "Auto Tuning Networking"
   Disable:
   cmd# netsh interface tcp set global autotuninglevel=disabled
   Enable:
   cmd# netsh interface tcp set global autotuninglevel=normal
   
4. If you are using proxy...
   Somehow msn read proxy setting from WinHTTP, which is not in sync with your system(IE) proxy. You can import IE proxy setting to WinHTTP by
   cmd# netsh winhttp import proxy source=ie
   Reset WinHTTP setting:
   cmd# netsh winhttp reset proxy

 Method #1, #2, #3 doesn't work for me. Finally #4 fix my problem.