Firefox won't open web pages after Catalina upgrade
I upgraded to Catalina (Mac OS 10.15.6) from High Sierra and now Firefox 79.0 won't open most web pages--it just displays a blank window and a little dot dancing left & right in the tab. A few web pages (e.g., support.mozilla.org) work OK. I restarted Firefox in safe mode; rebooted the system; and searched System Preferences/Security & Privacy in vain for a request from Firefox but nothing helps. Suggestions?
Also, Catalina crashes and restarts about twice a day, so far always when I'm out of the room, but I don't know if Firefox has a hand in it.