socket error 11004
That most probably means that you got the server name wrong in the account settings. If you post the entire error message, we could probably spot the mistake. Remove any unsent messages from the outbox (below the account folders in the folder pane), then compose a new test message with a unique subject and send it to yourself (i.e. from the account that's misbehaving to the same account). Post any error messages in your reply. You can click on an error message to select it, then use right-click to copy it and paste it into the text entry box.
When you reply, please give your build of the program and your version of Windows.
- To find your program version and build, in Windows Live Mail press Alt-F B.
- To find your operating system, press Windows key + R, type winver into the box and press Enter.