VMM does not have appropriate permissions to access the resource

Hello,

When I'm trying to add the Hyper-v server on the VMM-server I get the following error with WinRM:
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error (20552)
VMM does not have appropriate permissions to access the resource on the xxxxx server.

Recommended Action
Ensure that Virtual Machine Manager has the appropriate rights to perform this action.

Also, verify that CredSSP authentication is currently enabled on the service configuration of the target computer xxx. To enable the CredSSP on the service configuration of the target computer, run the following command from an elevated command line: winrm set winrm/config/service/auth @{CredSSP=”true”}
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The setup is as follow:

-hyper-v cluster running in the datacenter
-vmm-server (APP-controller is also installed) running on a different location.

The vmm server is up-and-running and I’m trying to add one of the two hyper-v server from the datacenter. I installed it as “windows server computer in a perimeter network”. The guide i used for the installation was from this website (only i took the install files from the vmm-server, not from the cd):
http://www.windows-noob.com/forums/index.php?/topic/11270-how-to-add-hyper-v-hosts-in-a-perimeter-network-in-vmm-2012-r2/

I added the hyper-v where the vmm-server is running on to check if my vmm server is running properly. So the problem is the connection to the datacenter. Of course i checked the Firewall if there where any blocks there.

Can anyone please share the possible resolutions/workarounds.

Thank you.