Free SSL Checker

This SSL Checker will help you diagnose problems with your SSL
certificate installation. You can verify the SSL certificate on your
web server to make sure it is correctly installed, valid, trusted and
doesn't give any errors to any of your users. To use the SSL Checker,
simply enter your server's hostname (must be public) in the box below
and click the Check Now button

https://www.thesslstore.com/checksslcertificate.aspx
.