SSL Organizational Unit

I RECEIVE AN ERROR“SECURE CONNECTION FAILED”

The following are the reasons:- Webserver employing older cyphers that are not supported by Firefox, such as sslv3.
The certificate has not been correctly installed.
The port for https connections is not open at this time.

Solution

Check and validate that the webserver on which you have installed the certificate is up to date with the most up-to-date protocol versions (make sure sslv2 & sslv3 are disabled)
Make a visual inspection of the certificate setup to ensure that the entire chain of certificates (domain, intermediate, and root) has been installed. In addition, confirm If the private key and the public key are identical, the private key is considered valid.
Check to see if the port that has been configured to accept the https connection of the corresponding URL is accessible.