A quick web search indicates that Hotmail made some change to their servers around that date. Go to Preferences > Accounts and check your Hotmail account settings. If they already match those below, you might try a search for the new Hotmail POP settings. Check the date of the web page, or posting, to make sure it's after November. These wre posted November 20th, 2012:
Hotmail Incoming Mail Server (POP3) - pop3.live.com
Authentication - USER/PASS
Port - 995
Hotmail Outgoing Mail Server (SMTP) - smtp.live.com
Authentication - LOGIN
Port - 587
Even if your settings match, it might not hurt to re-enter them while crossing your fingers. You might also try the Connection Doctor, under the Window menu. You might glean some useful information from that. And of course make sure it's set to POP, and not IMAP.