We’ve recently noticed that many publishers are having trouble logging into their accounts after the latest Mozilla Firefox update. A number of publishers have reported that they’re only seeing a sign-up page rather than a login form.
After a little digging and some testing, we’ve found that Adblock Plus, an add-on that sometimes gets installed with Firefox, can prevent you from accessing your account on the AdSense homepage. Our recommendation is to clear your cache and cookies and turn off the Adblock software before trying to log in at www.google.com/adsense. You may also wish to review our troubleshooting tips for login issues in our Help Center.
Thanks for bringing this to our attention!
Posted by Rajiv Sud – AdSense Publisher Support