The Firefox add-on needs an update ASAP.
Avast Password could not be verified for use in Firefox and has been disabled.
This message appears in the latest version update of Firefox with a link to this page (https://support.mozilla.org/en-US/kb/add-on-signing-in-firefox?as=u&utm_source=inproduct) where it says:
“Starting in Firefox version 57, only extensions built using WebExtensions APIs will work. Not sure if your add-ons are affected? See Firefox add-on technology is modernizing and these Frequently Asked Questions for details.”
Please update the add-on. Thanks, Joanie