Windows Live Mail Error 3204 

Starting yesterday morning (27th July 2013), my Windows Live Mail client began refusing to check for new messages on any of the Hotmail (com/co.uk/live.co.uk/live.com) accounts that I have configured (5 in total). All other non MS accounts (POP3 and IMAP) send/receive correctly, but the MS accounts all give the following error in the task queue window:

Unable to send or receive messages for Hotmail (z-systems) account.

Server Error: 3204

Server: 'https://mail.services.live.com/DeltaSync_v2.0.0/Sync.aspx'

Windows Live Mail Error ID: 0x8DE20003

The mails do download/show in the Windows 8 mail app and Opera Mail (apart from the live.co.uk which in opera mail shows no mail at all, but that's another issue).

I also have Windows Live Mail installed on another Win7 PC which seems to have no issues at all and continues to send/receive email.

Removing/re-installing Live Mail etc. has no effect, and switching the default account also does nothing.  No other mail client (including the Win8 Mail app) has the functionality I need so I do need to get this working.

Other users on this forum appear to be having the same issue and are having changes made to their accounts server side which seems to resolve their issues.

Can this please be looked in, thanks