I cannot sign in to YouTube to publish my video directly.

I can sign in to one account, but not the one I need to upload to.
Once I enter the email address for my YouTube channel I get:

"Couldn’t sign you in
This browser or app may not be secure.
Try using a different browser. If you’re already using a supported browser, you can refresh your screen and try again to sign in."

I have tried everything suggested in the online forums on this and nothing works. IT HAS BEEN A KNOWN ISSUE FOR OVER A YEAR! and there is still no fix.
Extremely aggrevating!