... suddenly I'm getting this message when I try to login:
It's not entirely clear when you see this error message. "When I try to login" would indicate that it happens when you launch the program and sign in, either automatically or manually. That is a separate process that determines which calendar and contacts to load. The error message refers to sending and receiving mail. So I'm guessing that you see the message after you've (been) signed in and when the program performs Send and receive messages at start-up.
Some users have experienced a conflict between these two authentication processes - the sign-in to Windows Live services and the log-on to the mail.live.com server - when the credentials (username and password) used are the same. A little troubleshooting experiment might test for this conflict:
- Press Ctrl-Shift-O for Options and on the General tab deselect Send and receive messages at start-up.
- Click the right-most button on the Home tab of the ribbon and select Sign out of Windows Live Mail.
- Wait until the default contacts list and calendar have loaded, then close down the program.
- Wait a few minutes for the program to complete its housekeeping, then re-launch it.
- Wait a few moments until the calendar, contacts and message databases have been loaded and the program is ready to receive commands, then click Send/Receive.
Do you see the same error message? The next step depends on the result of the experiment.