A critical certificate expired, and now many (most?) extensions cannot have their signatures verified. A fix is in progress, but if you need an immediate workaround... You can disable the add-on verification in Firefox for Android. Not recommended for long-term use, but to bridge this hopefully brief crisis: (1) In a new tab, type or paste '''about:config''' in the address bar and submit that. Click the button promising to be careful or accepting the risk if presented. (2) In the search box above the list, type or paste '''xpin''' and pause while the list is filtered (3) Tap the '''xpinstall.signatures.required''' preference to trigger a Toggle button and tap Toggle to switch the value from true to false Unfortunately, this creates the potential for a bad actor to serve Firefox an unsigned update, so it's definitely not a long-term fix. You can turn off extension auto-updating as a mitigation: (4) In the search box above the list, type or paste '''autoup''' and pause while the list is filtered (5) Tap the '''extensions.update.autoUpdateDefault''' preference to show a Toggle button, then tap Toggle to switch the value from true to false Hopefully this won't be needed for very long.