Why do I get a message that my Administrator is controlling my access when I AM THE ADMINISTRATOR AND ONLY USER?

This message indicates that an Enterprise Policy is controlling at least one setting in your Firefox. To see what it is, you can click that message on the Settings page, or type or paste about:policies in the address bar and press Enter to load it.

Probably you have at least one row on the "Active" panel (ignore the Documentation panel; that is the same for everyone). What do you see?

Note: a common policy to find is ImportEnterpriseRoots which instructions Firefox to trust certificates saved in the Windows certificate store, and not just the ones that Mozilla distributes as part of Firefox. This policy may be injected by popular security software because it reduces support issues for them when intercepting/filtering your web browsing.

I don't know how to change settings on Malwarebytes.

Could you describe the Malwarebytes problem in more detail?

Thank your for your response, but the Active panel is Inactive... Now what?

Maybe I was thinking of a different message than the one you saw. Where did you see the message that the Administrator is controlling your access?

I saw it when I tried to go to a site to get a medical discount card from pharmaceutical company; but I get that message often. It was not a scam site. It was a direct link from the company. I'm going to sleep now, so if you post again, I won't be able to reply until late tomorrow...