WLM 2011 unable to logon on to outlook server

Starting getting the following error message this morning.

Unable to receive messages for the Hotmail (removed for privacy) (IMAP version) account. Header download for the 'AAImportant' folder did not complete. Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity.

Server Response: AUTHENTICATE failed.
Server: 'imap-mail.outlook.com'
Windows Live Mail Error ID: 0x800CCC0F
Protocol: IMAP
Port: 993
Secure(SSL): Yes

Also dialog box pops up asking me to check logon details. have done but still get above message.

Been able to logon directly to email server via web.

Have been able to send a email to my email address.

Looking at other queries in this forum seems i am not the only person having such problems.

Any suggestions?

malcolm