What causes Windows Live Mail to fail with hotmail?

I've been having trouble getting Windows Live Mail to receive mails from my Hotmail accounts. I'm getting the following error when trying to send\receive:

Unable to send or receive messages for the Hotmail (X) account.

Server Error: 0x8007000E Server: 'https://m.hotmail.com/Microsoft-Server-ActiveSync' Windows Live Mail Error ID: 0x8007000E

The problem has gone away for short periods and then come back for days and weeks. What causes this and how do I fix it?