One of my two gmail accouns has suddenly become impossible to access (cannot receive, cannot send). T'Bird produces an Authentication has Failed notification, after a Google Window headed "Sign in to Mozilla Thunderbird Email" which refuses to go away. Clicking on the 'help' or 'privacy' options in that google window produces no more than a blank window but then "Sign in to Mozilla Thunderbird Email" reappears a few minutes later. My other gmail account doesn't have this problem, so I assume it's not gmail but it's T'Bird. What's going on? (BTW signing into this Support resulted in an email "New sign-in to Mozilla Support" warning "New sign-in to Mozilla Support to Firefox on Windows 10". Trouble is, I'm on Windows 11. Trivial maybe, but telling maybe.)