"You cannot create a subnetwork Message no. CN063"

Hello Experts

Pls guide me with this error....

"You cannot create a subnetwork"

Message no. CN063

Diagnosis

*You have not maintained all the parameters in Customizing which are necessary to create a subnetwork." *

I am using CN21 to create the Sub Network

I have maintained the combination in OPTP

The control key does not have cost ticked in the OPSU(Maintain Control Key)

I am wondering where am i going wrong

Pls guide me on the customization.

Thanks in Advance

Praveen B. K