Firefox: Untrusted Connection, Certificate Unknown

Quick Fix Firefox Error: Untrusted Connection, Certificate Unknown

Updated 29 Sep, 2016

If you’re running into a warning page upon accessing a website which you know used to work up until recent, it’s not always the website’s blame, it could also be a browser issue.

Sometimes the reason your access is restricted to a certain website is not just because that website has turned malicious all of a sudden, but for a browser issue.

Take a real case that happened to me lately as an example –

In the past few days, maybe even last few weeks, I’ve noticed I couldn’t go inside a well known website which I used to frequent from time to time.

popcorn time - connection untrusted

The error that displayed upon opening the website seemed familiar, however, unlike many times before when I encountered that error, this time, I could not go through it by accepting the risks.

At first, it seemed a bit odd. Nevertheless, I assumed the browser is always right and that it would be just a matter of days until the web-owner fix the issue.

As time passed by, I started getting more and more suspicious regarding that strange warning page that took the liberty out of my hands to choose whether I accept the risks involved in visiting that site or not.

It turned out that my hunch wasn’t unfounded, and that sometimes browsers themselves can be wrong as well.

Hence, to all who encounter a warning page upon accessing a website with the error message basically saying something along the lines of: “Secure Connection Failed”, know that there might be something you can do about it.

Ultimately, I’ve found a great Firefox support page which sums up most, if not all, of the security errors you may encounter with Firefox and the way you can troubleshoot them.

If you so wish too, simply click the link button at the bottom of the post and it will take you straight to that page.

However, to make it even easier on you to deal with the same issue I was facing before, I’ll also detail the steps needed to be taken in order to fix it, below.

Fix: Certificate Is Not Trusted Because It’s Unknow

Error code: sec_error_unknown_issuer

Apparently, the reason you’re seeing this error is maybe due to a corrupted file inside your Firefox browser profile.

To fix this, you’ll need to delete that file – cert8.db – while Firefox is closed. Don’t worry, it will be recreated when you restart Firefox. This is normal.

Open up your profile folder by clicking the menu button (), click help () and select Troubleshooting Information. The Troubleshooting Information tab will open.

Then, under the Application Basics section, click on Open Directory. A window with your profile files will open.

Close Firefox entirely (if you have more than one instance close the others as well), locate the file cert8.db and delete it.

Open up Firefox and verify that the issue is now gone.

popcorn time - certificate issue fixed

Troubleshoot “Secure Connection Failed”

The comment section is temporarily closed due to remodeling.