Clear the proxy settings in Windows Live Messenger.
 

    3.a. Start Windows Live Messenger. 
    3.b. On the Tools menu, click Options. 
    3.c. Click Connection in the left navigation pane. 
    3.d. Click Advanced Settings in the Connection Settings section. 
    3.e. Delete the content of the SOCKS field. 
    3.f.  Click OK two times to save the settings. 
    3.g. After you clear the proxy settings, verify if you are able to sign into Messenger. If you are still not able to sign into Messenger then please go to the next step. 

4.  If you are using Windows Vista, disable the Auto Tuning Networking feature:
 

    4.a. Click Start, click All Programs, click Accessories, and then right-click Command Prompt and choose Run as administrator. 
    4.b. Click Continue when Windows requests permission to continue. 
    4.c. At the command prompt, type the following command, and then press ENTER: netsh interface tcp set global autotuninglevel=disabled 
    Note: This command disables the Window Auto Tuning feature.
     
    4.d.  After you disable the Auto Tuning Networking feature, verify if you are able to sign into Messenger. 

 
5. If you are still not able to sign into Windows Live Messenger then please re-enable this feature using the information below and then go to the next step.
 

    Re-enable the Auto Tuning Networking feature by typing the following command at the command prompt, and then pressing ENTER:
     
    netsh interface tcp set global autotuninglevel=normal 

    Note: This command enables Window Auto Tuning again so that you can take advantage of the network throughput performance increase it provides.