For some reason it is now working and I haven't changed a thing, earlier Webroot wasn't showing up as an Addon Extension or Plugin under FF, it had just disappeared. It was there on 67.0.4 Then about 10 minutes later I checked and it was under Addon but was disabled??? Strange how it wasn't there and then was! Anyway I enabled and it's working.
Best answer by Ssherjj
Welcome to the Webroot Community,
Happy to hear that you resolved your issue,
Sometimes when Firefox updates, one will lose the Webroot Webfilter. So it is not unusual to have to check your browsers add ons and enable the Webroot Webfilter again. When FF updated yesterday I had to enable the WF as well.
Have a great weekend!