Yesterday since 8 am morning, Firefox extension is not working to all users worldwide. Neither the existing nor the new extension is not working. Users are not able to install new extensions too. Mozilla has replied this whole issue is due to certificate expiration and it is working to fix the issue immediately.
According to Mozilla, they are already rolling the fix to the users. This fix will be automatically applied in the background within a few hours. Mozilla also emphasizes that users would not need to take any additional steps before making add-ons working once again. If your extensions are not working, you should not try to delete or reinstall the extension because it might remove the accumulated data.
In conclusion, users wouldn’t have to worry because Mozilla is already working to resolve the issue. According to Mozilla, it is using the Studies system to fix the bug. So if you disable the feature, you might need to reenable the feature again to make sure the fix is applied.