Suddently, after many years, cannot access yahoo email account from windows live!

On Tuesday 7/23/13, my account suddenly stopped receiving email from my attached yahoo account.  Nothing has changed with this account and no settings have been altered on either yahoo or outlook.com (windows live).  It appears that outlook has not even made further attempts at connecting since sometime on the 23rd at this point.  Very cryptic message simply saying 'we couldn't get your messages. Make sure your user name and password are correct'.  I've double checked and re-entered the password and still no luck.  HELP!  This is getting critical.