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

Server Error: 0x80072EFD
Server: 'https://mail.services.live.com/DeltaSync_v2.0.0/Sync.aspx'
Windows Live Mail Error ID: 0x80072EFD

I receive this error when I sync the account to download messages. This account has worked well for many years. I have another account that syncs at the same time and it works just fine. I checked the outbox and it is empty. I'm at a loss where to go next.