and im using windows defender so its not a antivirus problem

Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connection certificates and send their own.

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites

https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

Websites don't load - troubleshoot and fix error messages

http://kb.mozillazine.org/Error_loading_websites

What do the security warning codes mean

https://i.gyazo.com/099f30baa2fee722814242bdf2406ac1.png

So far it only happens when im trying to visit youtube or google. As i said before i don't use any ANTIVIRUS beside WINDOWS DEFENDER.

I only have this error while trying to visit youtube or google. As i wrote earlier im using WINDOWS DEFENDER so there can't be any problem with ANTIVIRUS

Who is the issuer of the certificate if you click the link on the error page ?

Try to rename the cert9.db file (cert9OLD.db) and remove the previously used cert8.db file in the Firefox profile folder with Firefox closed to remove intermediate certificates and exceptions that Firefox has cached.

• https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean

If this has helped to solve the problem then you can remove the renamed cert9OLD.db file. Otherwise you can undo the rename and restore cert9.db

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Deleting cert9.db doesn't help its redownloaded and the error still occurs.

What do you mean by the issuer? I already added a picture with the advanced button press, what more you need to know?

Error code: SEC_ERROR_UNKNOWN_ISSUER

Regards

We would need to know the issuer of the certificate to be able to give more precise advice.

Can you post a screenshot of the certificate viewer page (about:certificate) that opens if the click the View Certificate link and that shows the issuer ?

Ok here

So far only google and youtube doesn't load becouse of this error, didn't have problem with other sites so far and they work just fine on different browser.

We have seen more cases recently with a Digicert certificate for Google instead of the certificate issued by Google Trust Services that you would expect.

• Organization (O):: Google Trust Services
• Common Name (CN):: GTS CA 1O1

Your certificate: Issuer: CN=DigiCert Global Root G1A

• https://support.mozilla.org/en-US/search/advanced?q=google%20%2b%20certificate&asked_by=&answered_by=&w=2&a=1&sortby=1

You can check the connection settings.

• Options/Preferences -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

Setting it to "no proxy" fixed the problem, kinda suprised it was the case since i didn't chance anything before and it worked just fine