When visiting the page for an addon at https://addons.mozilla.org/ , the "Add to Firefox" button, which is normally a nice, dark blue, is a "greyed out" hue of the same blue (see attached image), and my mouse turns into the red circle with a line through indicative of a "Do not go" symbol. This is thoroughly annoying. I've gone into my preferences, checked to make sure Firefox is updated properly, I'm signed into the addons page, I even checked to make sure addons were synced in my account but I just cannot get it to work! Any help would be appreciated.