Get-MobileDevice

Hey Guys

Trying to use tis command hhere : Get-MobileDevice -Identity

[PS] C:\Windows\system32>Get-MobileDevice -Identity robert
The mobile device robert cannot be found.
    + CategoryInfo          : NotSpecified: (:) [Get-MobileDevice], ManagementObjectNotFoundException

[PS] C:\Windows\system32>Get-MobileDevice -Identity 385A5FAD3184235CA0837514B8A6B917
The mobile device 385A5FAD3184235CA0837514B8A6B917 cannot be found.

I am following this link here and am trying to get mobile devices based on GUID and keep getting errors. The device clearly exists and I can get statistics another way, but to me the documentation says its should work.

https://technet.microsoft.com/en-us/library/jj218706(v=exchg.150).aspx

Thanks,

Robert

Robert