How to Fix Mozilla Firefox SSL Certificate Error?


Mozilla Firefox allows secured and private connection between the websites and browser; however, it won’t allow loading the site if it detects any security flaws. That’s one reason why Mozilla Firefox blocks the website with invalid or failed SSL certification and connection. Sometimes this detection can be falsely positive. Hence, we can try bypassing Mozilla security to access these sites.

Having a safe browsing environment is at the top of the priority queue for every user. In this regard, browsers such as Firefox have done their bits by incorporating different levels of enhanced tracking protection, but that is the job half done.

The websites have an equally important role to play when it comes to securing the data between the client and server. Two of the most crucial aspects in this regard are that the websites should follow the HTTPS protocol and have an SSL Certificate.

The latter one, Secure Socket Layer, verifies that the transfer of data between two servers or a server and the user is taking place in a safe and encrypted manner.

If a site doesn’t have this certificate, then there are high chances of the data getting intercepted in between the exchange process.

But what if a site doesn’t have this certificate?

Well, in these cases, your browser will warn you and advise against proceeding ahead. In the case of Firefox, you might get error messages such as the Secure Connection Failed, This Connection is Untrusted, among others.

Fortunately, there do exist a few workarounds through which you could fix these Mozilla Firefox SSL Errors. And in this guide, we shall make you aware of just that. So without further ado, let’s get started.

Clear SSL StateIn some instances, when a website updates its SSL state, it might take a while before it’s ultimately reflected on your end. The reason for that might be due to the accumulation of quite a few cached SSL data.

Likewise, corruption of these data could also lead to certificate-related issues. So in all these cases, you should consider deleting the stored SSL State of your PC.

Head over to the Start menu and search and open Internet Options.Switch to the Content tab, and click on Clear SSL State command option.

It shall refresh the SSL certifications for the websites that it had stored to date.Hit on Apply followed by OK to close.Now launch Firefox and visit the concerned site, check if the SSL Error has been fixed or not.

Deleting the SSL State wouldn’t adversely affect your interaction with that site. Rather, the next time you visit that website, the browser will re-scan for the available SSL certification, and if found, will update its database accordingly. And this re-population of the data might fix the underlying issue as well.

Disable Firefox ProxyIf you are using a Proxy server, the browser might not get hold of the correct SSL certificate corresponding to your region and time zone. For the unaware, an incorrect time of the system is among the most common culprits for this issue.

The thing is, when the publisher updates its SSL certificate, it might not get synced with your PC if the latter is using an incorrect time zone. Therefore, you should consider disabling the Firefox proxy feature, which could be done as follows:

Launch the Firefox browser.Click on the menu situated at the top right.Select the Settings menu from the list.Scroll to the Network Settings section.

Click to open Settings… button.Switch to No Proxy mode, and hit OK.

Now restart Mozilla Firefox and verify if the SSL Error has been fixed or not.

Disabling proxy might restrict your ability to browse geo-restricted contents, but at the same time, it is equally important to get hold of a site’s correct SSL state, so one shouldn’t hesitate for this trade-off.

Disable Antivirus Network ScanIf you are getting the SSL error across every other site you visit, it might have to do something with the antivirus software.

In some instances, it might act a little bit overprotective and could raise an incorrect flag, even if the site is following all the safety protocols.

To check or verify the same, you should consider disabling your antivirus network scan feature temporarily. If it fixes the underlying issue, then it’s better to keep that functionality disabled.

With that said, here’s the list of major antivirus software and the network feature that you need to disable/enable to fix the Mozilla Firefox SSL error.

Avast and AVG: Disable Enable HTTPS Scanning.Bitdefender: Disable Encrypted Web ScanBullguard: Disable Show safe resultsESET: Disable SSL/TLS protocol filteringKaspersky: Enable Do not scan encrypted connectionsIf turning off the network scan feature does rectify the issue, you should consider keeping that feature disabled. As far as online protection is concerned, you could consider using Windows Defender and Firewall applications.

Change Firefox SSL SettingsApart from the Root Certificate that each site needs to have, an additional intermediate certificate acts as a bridge between the root and your system. And every website needs to give an equal weightage to this certificate as well.

If that is not the case, then the browser might refuse to establish the connection with that concerned site. While adding that certificate is in the developer’s sole hands, you could consider disabling the intermediate certificate check from your end.

Here are the steps to change the SSL check in the Firefox browser:

Launch Firefox browser, and head over to the about:config page.Click on Accept the risk and continue command to proceed.

Search for security.ssl.enable_ocsp_stapling configuration.Change its value from True to False using the toggle switch.

Once done, restart the browser and see if it fixes the Mozilla Firefox SSL error.

While the intermediary certificate is used as a bridge between the root and the client, its importance cannot be neglected from the security point of view. Therefore, it’s usually better to keep that flag enabled and only disable it when accessing a site is crucial.

Manually Add CertificateIf you have a valid and authorized CA, you may manually add the same to the browser. This way, you wouldn’t have to wait for the browsers to scan the site for the certification or stamp their approval.

Here are the steps to add the certificate in Mozilla Firefox:

Launch Firefox and head over to its Settings page from the menu bar.Search for Certificates under the settings search bar.

Click on the View Certificate… button from the search results that appear.Switch to the Your Certificates section, and click Import… button.

Select the CA-approved certificate file from the local disk, and hit OK.The SSL certificate will now be imported to the browser, and you may now access the site without any issue.

Getting hold of a valid SSL certificate might prove to be a challenging task, more so if you don’t have the required permissions. If that is the case with you, consider trying out our other fixes mentioned here.

Bypass SSL WarningSome sites have an SSL certificate incorporated in their sites, but any authority hasn’t approved that. Rather, they are self-signed certificates.

Some browsers, including Firefox, might throw up an error message while encountering such a certificate. But at the same time, they also give you the option to bypass this warning and access the required site.

So if you are quite sure about the site’s validity and trustworthiness, and wish to bypass that error message, then click on the Advanced… button next to the error message. After that, click on Accept the Risk and Continue, and you shall be taken to that site.

Do keep in mind that accessing sites with a self-signed certificate might still possess some security risks, so only access them if it is of paramount importance.

Bottom Line: Fix Firefox SSL ErrorWith this, we round off the guide on how you could fix the Mozilla Firefox SSL error. We have shared six potential fixes for this issue.

In my case, the site had updated its certification in the backend. However, it wasn’t getting reflected from my side. Upon clearing the SSL cache stored on my PC, the issue was rectified.

Do let us know in the comments section which of the aforementioned methods managed to spell out success for you.

Lastly, here are the recommended web browsers for your computer and mobile phone that you should give a try.

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