Here we are, May 19, 2014 and back to sync error.   SERIOUSLSY!!!

Unable to send or receive messages for the Msn (xxxxxxx) account.

Server Error: 4201
Server: 'https://mail.services.live.com/DeltaSync_v2.0.0/Sync.aspx'
Windows Live Mail Error ID: 0x8DE00002

Original title: Server Error: 4201