Actually cw1988 is correct - and use another "bayxxx-m.hotmail.com" server may help.
To make an already long story shorter, we tried Microsoft Community forums which didn't help.
Best help we got with this was through posting on Outlook.com's facebook page where the reps on there were helpful and very responsive.
Your phone is auto-configured when you setup your account by geolocation, hence the assignment of a different server in the settings depending on where you're setting the account-up from.
The server(s) your phone is interfacing with isn't syncing and needs to be restarted after some updates.
Some services like IMAP are failing. MS does not know about the issue in your particular area.
By politely working with the reps on the Outlook.com facebook page, I was able to have them restart some of the offending servers.
That night the problem was solved.