Disable the Auto Tuning Networking feature:

1. Click Start, click All Programs, click Accessories, and then right-click Command Prompt and choose Run as administrator.
2. Click Continue when Windows requests permission to continue.
3. 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. After you disable the Auto Tuning Networking feature, verify if you are able to sign into Messenger.

5. Reboot the PC