How to Fix Secure Connection Failed Error in Mozilla Firefox
If you have done all client side fix but no luck then try server side. Below suggestion helped me to quickly solved my problem It looks like the issue with Firefox is most likely being caused by the cipher suites the server has enabled. I scanned the site using SSL Labs here: https://www.ssllabs.com/ssltest/analyze.html?d=faceawards.nyxcosmetics.com.tw, and it shows a few ciphers suites enabled, but none are supported by Firefox so a secure connection cannot be created. I would recommend running a tool called IIS Crypto ( https://www.nartac.com/Products/IISCrypto ) on your server and select the option to enable "Best practices", this will ensure you have secure ciphers that are supported by all browsers enabled on the server. If you don't want to download the IIS Crypto utility on your server you can also edit the ciphers directly through the Windows SSL Configuration Settings ( https://docs.microsoft.com/en-us/windows-server/security/tls/manage-tls#configuring-