Good old "An error occurred while using SSL configuration for endpoint xxx.xxx.xxx.xxx:443. The error status code is contained within the returned data." With a twist. There are many sites, only one fails. Tried reselecting the certificate in IIS, this is a cert that has been working for a long time and is the same across all sites. The same set of sites are working on other servers with the same certificate configuration. This is not Exchange related, these are custom .net applications. Any ideas?