how to a website SSL certificate is valid or not?

I got an issue from my client regarding the SSL setup for his website. I'm not familiar with the SSL certification setup process. He is saying that We have an SSL certificate for this server but I can’t tell if it’s setup properly or not.

If I open that website, firefox says Warning: Contains unauthorized content. I am seei开发者_StackOverflow中文版ng some details in the warning message window which are given below:

Web site: mydomain.com
Owner: This web site does not supply ownership information
Verified by: Not specified

Mainly I want to know whether the SSL certificate used for this site is valid or not. Can anybody suggest a way to check for the SSL certificate validation of a website.

Thanks

Telnet the server on port 443. If it is responding then it is a certificate problem

To install certificate Check this