Make sure you are not blocking content.

https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop also see https://blog.mozilla.org/security/2021/03/23/introducing-smartblock/

https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection

Diagnose Firefox issues using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

Tracking protection off does not help. Troubleshoot mode still has problem. Clearing cookies and cache doesn't help.

of things trying these were i did earlier, but then again after suggestion.

Delete browsing, search and download history on Firefox {web link}

Remove a single website from your history {web link}

Open the History Manager <Control> (Mac=<Command>) <Shift> H. In the search bar, enter the name of the site. Right-click on one of the listings and select Forget About This Site. This should remove all information, including any site settings And Passwords.

Made forget specific sites, not working. Made forget all sites, all data, not working.

Usually i don't keep search and form data anyway but selected for delete it with the rest.

ok so, for proxy? was trying with kaspersky safe kids, did not block these sites, because didn't want, but only having it broke page loading. Didn't affect other browsers, others were always working. uninstall and it works. but why i don't know. Fixed though.

That was very good work. Well Done.