firefox is extremely slow or fails to load sites

For the past few days to a week Firefox has failed to load some websites such as Amazon or Login.gov. I tried accessing the same sites using Edge and it worked fine. So it is not a problem with the sites. I do not believe I have changed my settings, although there is a new version of AdGuard which may have something to do with it. I believe the problem started with the update of Firefox on Nov 18, however. I am using Duck Duck Go, but have the same problem using Google as my default search engine. I do notice that I have a message in settings saying my browser is being managed by my organization and showing this : ImportEnterpriseRoots. I am an individual user, so am not sure what that means or if it is related. In any case, I need help figuring out how to fix this. I do not want to use Edge but may have to if I cannot get this fixed.