Negotiate over HTTP error
When you scan a Citrix XenDesktop Site you see the following error
"The Citrix XenDesktop site agent encountered an exception when 'Connecting to the Citrix server using HTTP'. Connecting to remote server failed with the following error message: The WinRM client cannot process the request. Default credentials with Negotiate over HTTP can be used only if the target machine is part of the TrustedHosts list or the Allow implicit credentials for Negotiate option is specified. For more information, see the about_Remote_Troubleshooting Help topic."
The Citrix XenDesktop Site Agent uses Microsoft Windows PowerShell to gather information from the remote site. This error is seen when custom credentials are being used and the trusted hosts have not been configured for PowerShell.