Can't login to Yahoo Mail -- keeps going back to login


New Email
I can't login to Yahoo mail on one specific account. It keeps taking me back to the login page requesting my password. I know the password is correct and I've also changed it a few times going through the reset process.

The page does in fact 'welcome' me with my name so it appears that I am logged into Yahoo... but can't get into my mail.

I've tried two different browsers... clearing them completely of all cache and cookies.
I've tried three different machines with two different operating systems.
I've tried accessing mail from Yahoo chat -- no luck.

I can login to Yahoo mail with a different username and passwords... but not my main Yahoo mail account.

I did try the suggestion below to change my screen resolution to 800 -- that didn't work... I didn't get the notification that the resolution wasn't correct.

Any assistance would be appreciated.