Screenshot below

Make sure you do not run Firefox in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History).

• https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history
• https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing

• Settings -> Privacy & Security
  Firefox will: "Use custom settings for history"
• remove checkmark: [ ] "Always use Private Browsing mode"

I figured out the CORRECT answer ... In Firefox, open menu (3 horizontal lines at top right) Select SETTINGS Select PRIVACY AND SECURITY Scroll down to HISTORY Under "Firefox will" item, select USE CUSTOM SETTINGS from drop down menu Uncheck [ ] ALWAYS USE PRIVATE MODE

Additionally, delete any shortcut that was always opening Firefox in private mode. Replace with a new (not corrupted) shortcut.

This corrects the problem of having to sign into sites every time you access them.