This error occurs when you are not connected to the internet, check
your internet connection and make sure it is working properly.
The most likely cause for this problem is that your firewall
does not allow Messenger to access the internet. This happens often if
you install a new version of Messenger. Make sure Messenger is allowed
access in your firewall rules. See our article on using Messenger through a firewall application.
This error might also occur if a proxy server is enabled in
Messenger or Internet Explorer while you do not use one. To remove the
proxy settings, click the "Tools" menu and then "Options..." at your
Messenger main window. Then in the options screen click "Connection" in
the list to the left. Next, click the "Advanced Settings..." button.
You can try and uncheck all checkboxes in this screen except the one
labeled "TCP" to let Messenger connect through a direct connection. If
that does not work you can restore the settings again by checking the
boxes you unchecked before. Source
Please rate this solution.