My firefox 80.0.1 on my iMac running 10.13.6 has been unable to access the moz://a server for about 1 year!
As stated, my edition of Firefox on my iMac is cut off from access to Moz://a server. So any offered upgrades, reloads, fixes, are not able to be accessed. All I can get are these offers from Firefox via email. To access Moz://a server, I'm writing this on my dependable "Opera" browser. Safari browser is also badly skewed; displays huge letters so that a word covers more than my display screen.
Doing OK with Opera browser the last year. Would be nice to download a new, functional Firefox browser but am shut out from access to Moz://a server if attempted through Firefox.
Suggestions are welcome.