Windows Message: Requested Session Access is Denied
Microsoft Remote Desktop Services and NComputing vSpace require that users be granted access to Windows Remote Desktop Services in order to access a windows session remotely. This requirement applies to all NComputing access devices connecting to a vSpace 6 environment. Failure to correctly configure your Remote Desktop Services settings can result in devices being unable to connect or the display of session access errors.
Please see the attached PDF as an example on how to configure Remote Desktop User access on a Windows 7 environment.
You can also see the following article related to 2016 deployments: