To make Firefox stop "Connection not secure" complain

How to make Firefox stop complaining about “Connection not secure” for a specific website?

It depends on the specific error code:

You may need to remove the site from exceptions to see the error code.
If you have no control over the site, there’s not much you can do other than notify its administrator and use security exceptions.

Thanks for replying.

Error code: MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT

Long time ago, a user can manually trust a self signed cert.

Can it still be done now?

If you own the site, it’s best to regenerate its certificate, e.g. using Let’s Encrypt or your own private CA such as XCA that you can export and deploy to the clients.

If you are limited to a self-signed certificate, there’s the proper method that you should use to generate it, but it may not work for global TLDs.

If regenerating the certificate is problematic, adding security exceptions can be considered safe enough as it stores the certificate’s fingerprint:

find ~/.mozilla -name cert_override.txt -exec head -v -n -0 {} +
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So as User, I can only add exceptions via my browser.

The site in question is my OpenWRT router’s Luci management frontend.

I followed the “proper method” to create a new KEY and CERT with the suggested extension file contens. I am still getting the same error:

openwrt.lan uses an invalid security certificate.
 
The certificate is not trusted because it is self-signed.
 
Error code: MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT
 
View Certificate

Thank you for introducing XCA to me. I will try using it next.

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