I am having an issue with not being able to make a payment on a specific site: www.walmart.com since upgrading to Firefox 76/77. I am using: Windows 7 on desktop PC When on Walmart.com with items in the shopping cart, I have the option to "proceed to checkout." This usually loads a new screen in the same tab - not a pop up box. This time, however, I only got a white screen with continually spinning circle. Attempted fixes: Verified with Walmart that they could indeed access my checkout Verified that I could access the checkout in another browser, Internet Explorer Tried turning off enhanced tracking protection cleared cookies Disabled ad blocker Unchecked Block Pop Up windows re-checked Block Pop Up windows and created exception for www.walmart.com Upgraded to Firefox 77 None of the above had any effect. I have no Add-ons to disable. I'm running a pretty basic system. I was finally able to make my purchase on a different computer that was still running Firefox 75. Thus, I have narrowed the problem down to the upgrades of Firefox 76 and beyond. I was also able to make a purchase on a different site using Firefox 76, but I don't recall if that site needed to load a new screen for checkout. Still, www.walmart.com will not cooperate. Any ideas what else could be blocking this particular site?