missing step in "Potential Security Risk" error KB

[Morku]

When you follow https://kb.adguard.com/en/windows/solving-problems/connection-not-trusted you still will have certification error in Firefox.

Step 8 says: 8) Browse the downloaded cert.cer file and click Open.

When you do, you get this screen:

Now Step 9 says: 9) Click OK.

This will not solve the problem. Even after browser restart, you get a certification error.
It's important here to check the Option: "Trust this CA to identify websites."

With that check, browsing and filtering works fine.