During a recent deployment of SharePoint 2013 for a client, we came across an issue with Central Administration getting the error:.

Generally this is resolved by adding the CA site as a Trusted Site.  The client required that trusted sites be added via GPO.

The client added the site to the GPO and we forced a refresh.  We still had the same issue.  After checking internet settings, we found the trusted site was not set.  We attempted reboots and GPO refresh forces to no avail.

IE ESC had been turned on for both Administrators and Users on the server.  After disabling IE ESC, the trusted sites were properly applied and the error disappeared.