I could not log on to addons.mozilla.org
I click on 'Register or Log in'. This produces a panel with my photo, email address and a blue bar marked 'Sign in'. There was no place where I could enter my password. When I clicked on 'Sign in', a red bar appeared marked 'Invalid parameter: state' and there did not seem to be any way past that.
I deleted the tab and tried again After several attempts, the problem went away and I was able to log in.