profile manager profile installation failed the scep server configuration is not supported

Hi;

I am trying to setup a number of iPads in school that for whatever reason have not be managed centrally by our MacServer.

On one of the devices I am unable to install the Enrollment Profile I receive the message:

Profile Installation Failed:

The server certificate for "https://macserver.(our schools domain name/devicemanagement/api/device/auto_join_ota_service" is invalid?

I also have several other issues with other devices which I will highlight separately.

Thanks in advance.