This video of Biden admitting who he works for plays just for me. see screenshot https://www.youtube.com/results?search_query=biden+admitting+zionist

Can you show what you're getting? What security software are you running? Windows home or pro?

Did you try clearing the browser cache? https://support.mozilla.org/en-US/kb/how-clear-firefox-cache#

You can also clear all items for a single site. https://support.mozilla.org/en-US/kb/remove-websites-address-bar-suggestions

Does it happen with Firefox in Safe Mode?https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

Thanks for the hints!

Cleared the cache - same issue

Started in Troubleshooting mode - same issue

Win10-64 Pro fully patched, MS Defender

Thanks for the pic. I always get that when connecting to my router. Just click Advanced and then the next option Accept the risk and continue.

Got error msg: "Someone could be trying to impersonate the site and you should not continue.

Websites prove their identity via certificates. Firefox does not trust www.youtube.com because its certificate issuer is unknown, the certificate is self-signed, or the server is not sending the correct intermediate certificates.
Error code: SEC_ERROR_UNKNOWN_ISSUER
View Certificate"

When I click Advanced I get attached jpg (The FIRST time I did this I got a bunch of text code, but this has not recurred). This jpg shows a bunch of Google certs

Your screenshot is the option to view the certificate, I can replicate that. see screenshot Post a screenshot the option you get after clicking Advanced from the first screenshot. You should be able to click Accept the risk and continue to move forward.

Just for S&Gs you can try this option if you're up for it. IMHO you should have this available for testing issue like this. https://www.howtogeek.com/399290/how-to-use-windows-10s-new-sandbox-to-safely-test-apps/

Here is what I get after clicking Advanced:

Virtualization is Disabled.

I am tired now. I will enable it tomorrow am when I get moving again.

Thanks for all your efforts!

Good night.  ;-))

Does it still happen in a new profile without signing into sync? An easy way to test a new profile is to install Developer Edition and see if it happens there or refresh your existing profile.

Refreshing Firefox fixed everything!

Thank you all for your help !!!

Glad to hear. Mark it as resolved to get it off our list of issues and have a nice day.