How to get through security error pages in firefox browser?

Question

I'm aware that we use thisisunsafe in Chrome to bypass such error pages but how can I bypass such pages in Firefox? I get the following error when I load the page:-

Firefox detected a potential security threat and did not continue to <site> because this website requires a secure connection.

<site> has a security policy called HTTP Strict Transport Security (HSTS), which means that Firefox can only connect to it securely. You can’t add an exception to visit this site.

I tried the following steps to resolve it but it didn't solve the issue:-

1. Opened a new tab and entered about:config
2. Clicked on Accept the Risk and Continue
3. In the search field, type in security.enterprise_roots.enabled and hit enter
4. I saw one field which was already enabled true
5. Didn't know what to do next as the field was already enabled true

I'm looking for a workaround of thisisunsafe in Firefox.

Koressa

Answer 1

1. In the Mozilla Firefox address bar, type about:config
   
2. Look for network.stricttransportsecurity.preloadlist
   
3. And set the last field Value to false and restart the browser.

Koressa

No longer working in Firefox 95.02 – Displeasure

Didn't work in 99.0.1 either – Ranaerancagua

Working for Version 98.0.2 @Displeasure – Koressa

@NehaChaudhary Nice, it seems that they've fixed it. Thanks for pointing it out, I'd completely given up on this. – Displeasure

If it doesn't work try: about:config in Firefox and change the security.enterprise_roots.enabled option from TRUE to FALSE. – Achates

Answer 2

As of April 5th, 2022, this is how I bypass the You can’t add an exception to visit this site. with Firefox 98.

If you see this without the Add Exception button :

1. Open the Preferences of Firefox:

2. Open the Privacy & Security tab:

3. Scroll down to Certificates and click on View Certificates...

4. Open the Servers tab and click on Add Exception...

5. Fill in the Location field and click on Get Certificate:

6. Click on Confirm Security Exception:

7. You should now see your exception, click on Ok:

8. Reload your page and you should now be able to see your website :)

Danford

v 101.0, localhost, not working :( – Brandy

Doesn't work in Fx 116, still the same error page appears. – Aquamarine

Why does this happen on some wifi networks but not others? Is there some type of Firewall trying to do HTTPS filtering? – Muenster

Answer 3

About changing the network.stricttransportsecurity.preloadlist value, restarting the browser may not be enough; in my case I had to manually clear the cache for it to work.

Lacker