CIFS Kerberos delegation PowerShell Double Hop

Hi,

in 2012 R2 environment, I want to perform the following task:

ComputerA initiates a Remote PowerShell Session via Kerberos Auth. to ComputerB. (works fine)

Within that Remote PowerShell Session, we try to access a file share on ComputerC.

When ComputerB is allowed to delegate all Kerberos services, it works fine.

When I want to use Kerberos constrained delegation on ComputerB to CIFS/ComputerC it fails

Computer C does have the CIFS SPN registered.

Does anyone have any idea what else is required to makre this work with Constrained Delegation?

Thanks

KR

Chris