You can activate approval steps for QA systems only

What causes this issue?

You want to give an approval step the status 'Active'.
You can only do this for systems that are QA systems in the transport
route configuration.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Make sure that you want to activate an approval step for this system.
Find out why the system for which you want to activate the approval
step is not a QA system. Contact the system administrator for help.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.