How to bypass the "secure connection failed" warning in Firefox 33

Since installing Firefox 33 a "Secure Connection Failed" error is no longer bypassable using the
"I Understand the Risks" button - it's gone!

Is it still somehow possible to ignore certificate errors? (e.g. for lazy use in local environments)
_{Error code: sec_error_invalid_key}

Solution 1:

Open Firefox's about:config

Set security.tls.insecure_fallback_hosts = www.domain.com (substitute the domain you're having the problem with)

Reload the page

Solution 2:

This problem has been reported to Mozilla in their support forum.

The reason is that Firefox 33 has fully switched to the more strict libPKIX and you can no longer disable this library and fall back to the previous NSS code.

See related Mozilla blog post and bug:

Bug 975229 - Remove NSS-based certificate verification

It appears that they will not change this behavior.

If your problem is like mine, on a webmin site, try recreating the certificate from inside webmin. It helped me get back the "make security exception" in FF 33.0!