I accepted the request to install webex extension and while the extension was installed all my saved id/passwords, browser settings, and bookmarks, were lost. really quite unhappy about how this turned out.
All plug-ins will be disconnected when you turn on the computer on May 4, 2019, but the reason for adding failure is that the network problem cannot be downloaded. If you have this problem, copy and paste it. Thank you for your cooperation.
It simply does not install with Firefox 66.0.3 -- Don't even bother. And if you are outside the U.S. in a non-English-speaking country don't try to get to an English language website for help. Bottom line: even trying to install this is a profound waste of time.