Oct 2, 2021, 2:13:52 AM10/2/21
Dealing with the expired certificate issue, I encountered a deficiency on some 'recent' Firefox versions.
The instructions stated:
From the main menu in Firefox, select Tools | Options. Click Advanced on the left, and select the Certificates tab on the right.
However, on both Firefox_45.5.0.exe and firefox-45.9.0-2.exe, the tabs did not exist. I opened an older version, Firefox 45.5.0 Beta 8 (2017-05-19), and the tabs are displayed.