How to remove non existing primary server from ZCM

Hello,
I installed a second primary server (ZCM 11.2) but the machine did not function right. So I wanted to remove that server from ZCM, but it is not complete.
I followed the instruction that says: Go to Configuration tab, Server Hierarchy en Delete the primary server there.
So far so good, but the machine is still in the list of Devices\Servers.
I cannot delete the server there. It says: the object is a Primary Server and cannot be deleted. Even when the server is powered off.
Anybody a suggestion how to get rid of that server in the device list ?

Thanks in advance.

Regards
Gert