There are several things that can cause this vague error message. The most common reasons we have seen are as follows:
- A firewall or router is blocking access on your network on port 443.
- The private key for your certificate does not match or is not associated correctly with the certificate.
- The DNS entries for the web site are configured incorrectly.
- The web server is not configured to run on port 443 for https requests.
- The web site is not the IIS Default Website and has not been bound to an IP address for https requests. (IIS defaults this to “All Unassigned”).