Resolving "Could not establish trust relationship for the SSL/TLS secure channel with authority 'localhost'" in IIS with WCF web services

If you get an error that looks like "Could not establish trust relationship for the SSL/TLS secure channel with authority 'localhost'" in IIS while testing WCF web services, it most likely means that you haven't correctly specified the certificate for your service in IIS. If you're certain you've correctly specified the certificate, it most likely means that the IIS user doesn't have access to it, so you'll have to go in and manually grant permissions for it.