This means your certificate's domains do not match the domain where this certificate was installed to. For example, your certificate was created for www.yourdomain.org and yourdomain.org, but you decided to use it on support.yourdomain.org as well. In such case, when visiting support.yourdomain.org you will see this error.
How to fix:
Make sure you did not install a certificate to this domain that does not include this domain.