This error occurs when you are connecting to Outlook. How to troubleshoot RPC over HTTPS when it fails through Outlook?
It occurs when one of the following statements is true:
- The common name on the certificate does not match the fully qualified domain name (FQDN) . (ie. common name is ssl247.net and client is accessing by http://subdomain.ssl247.co.uk/)
- The client’s computer does not trust the certificate authority.
- The certificate expired.
Note: If there is a problem with the certificate with RPC over https, the client will not be prompted an error message. The connection to the server will just fail.
You must test your connection to the FQDN by a browser to troubleshoot this problem. This should prompt you with one of the follow errors given above.
1. If the error is a common name mismatch: You must adjust your server to match the common name and the certificate or replace your certificate to match the FQDN inputted by the client.
2. If the error is a certificate authority not trusted or expired certificate error, make sure the intermediate and signed certificate(s) were installed correctly. The Installation Health Checker will help you to check it.
3. Ensure that the SAN is added to the certificate.