I ran into a problem with Firefox and I'm not sure how to get more diagnostic information. When I have a long running session--the only time I've seen this happen is when I've started firefox in the morning and left it running all day--it stops loading pages. I.e. any navigation be it opening a bookmark, a link or reloading a page does nothing. The throbber shows activity, but nothing else happens. If I have the developer tools open, the network tab will show the initial GET request, but it never completes. It happens very sporadically--I had disabled the only extension that interferes with page loading (Load Background Tabs Lazily) and thought that fixed it only to have the same problem about a week later. Network connectivity is fine during this instance, I can ping or use curl to reach the sites in question. Also I can see new processes spawning in Task Manager if I open the link in a new tab or window. Given how long Firefox needs to run before exhibiting the issue and how rare it is the normal procedure of working from a fresh profile would be difficult. So I'm hoping there's something in the about:xyz pages that would shed some light on what's going on. At the moment the only thing I can think of is use wireshark to determine if Firefox is even making the request or not (and either way, that doesn't lead me to anything actionable). Platform is Windows 7, 64-bit, Firefox 88.0.1