I now see Firefox extension on the downloads page (https://www.enpass.io/enpass-beta-downloads/). After installation this version doesn't fail connecting to the Enpass assistant. Instead I see the Enpass popup window with the option to Allow or Reject the connection from Firefox. Clicking the Allow button appears to refresh the window, nothing else occurs. Reject closes the window till I click the toolbar icon again.  If I inspect the browser authorizations in the Enpass app preferences