Does this help

• deleting cookies_delete-cookies-for-a-single-site

If clearing the cookies doesn't help then it is possible that the file cookies.sqlite that stores the cookies is corrupted.
Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete other present cookie files like cookies.sqlite-journal in the Firefox Profile Folder in case the file cookies.sqlite got corrupted.

Any chance that you've installed an extension that adds out-out cookies?

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

Cor-el, I am not knowledgable enough to follow the steps that you recommended for me to try example: cookies.sqlite. and cookies.sqlite I need simpler language to follow. Thx, Ira.

In Windows usually if you can find and see a file then using a mouse right click will give options including renaming that file. Renaming cookies.sqlite to something like cookies.sqlite.old1 puts the file out of use; whilst leaving open the option to rename it and reuse it if necessary.

The easiest method of finding the file, (it resides in your Firefox profile) is to use:

• Firefox Button -> Help -> Troubleshooting Information -> Profile [Open Containing folder]

Firefox will rebuild a file of the correct name next time you restart Firefox. Deleting or renaming the files removes your cookies and as you continue to use Firefox cookies will be added and set as normal.