I'm getting a 400 bad request on fire fox for my home page that was woring until this morning.

If you open the same site in Private Window, does it work there?

It works on Bing and my cell but not here on firefox

Everything was fine until this morning

Hi

What is the address of the site that you are trying to view?

https://currently.att.yahoo.com/

They just saved too much crud with you over time.

It generally should work in a Private Window, but you might need to do some cleaning up before they can handle their own mess. Click the shield icon in the toolbar next to the address and do "Clear cookies and site data" while on that error page. It might log you out and reset some site preferences, but should be enough to let you in again with a clean slate.