I have Firefox 66.0.3 on Ubuntu 18.04, Ubuntu 16.04 and windows 10. Since last night, all Firefox add-ons on the Ubuntu 18.04 machine stopped working and cannot be reinstalled (connection error). Add-ons are fine on other platforms. Just minutes ago when I started to write this review, everything got back to normal.

I mistakenly pressed the update button! And now wasting time to downgrade mozilla, restore my pages and get the adblock, which is somehow blocked!
Maybe I should try opera, as recommended by a friend recently!

Firefox is playing with fire, the community will revolt with this attempt to boycott the extensions that give us freedom as the adblock.