Unable to synchronize with imap-mail.outlook.com, server response AUTHENTICATE failed.

Split from this thread.

Sorry, I missed your earlier reply. Thanks for confirming that we're talking about Windows Live Mail.

1. Is this account also set up in Outlook 2016?
    
2. The account name indicates that this is the second instance of the account. Has the other one been removed, or just deactivated?
    
3. Did you set up this IMAP account before or after the account was migrated from Outlook.com to Outlook Mail?
    
4. Are you signed in with this same account? Point at  the account button to find out:
   

The original chap seems to have gone quiet, though I get the same issue as him:

Windows 10

Windows Live mail using a Hotmail account

INCOMING

imap-mail.outlook.com

993

Requires SSL SSL = Yes

Clear text

OUTGOING

smtp-mail.outlook.com

587

Requires SSL SSL = Yes

Requires authentication= No

It's been working for ages as IMAP and yesterday this error comes up. I am 'signed in' (looking at your screenshot with the same account as my Hotmail address. If I 'sign out' the issue is still there anyway.

AUTHENTICATE failed.

Configuration:
   Account: Hotmail (xxxxxxxxxxxxx)
   Server: imap-mail.outlook.com
   User name: *** Email address is removed for privacy ***
   Protocol: IMAP
   Port: 993
   Secure(SSL): 1
   Code: 800ccc0f

Obviously I can still access my Hotmail via the outlook webpage.

Any ideas?