&4 You cannot set this scenario to operative

What causes this issue?

You cannot set this scenario to operative.
When you set a scenario to operative, the system tries to set all
marketing projects in this scenario to active. In addition, the system
sets all marketing projects in other (not operative) scenarios to
inactive.
If the system is not able to change the active state of any of the
marketing projects, it is not possible to set a scenario to operative.

System Response

In this case, the system cannot set the scenario to operative. The
system generates error messages for each marketing project that it
cannot set to active or inactive. See these error messages for more
information.

How to fix this error?

See the error messages for the marketing projects in question to
determine the cause of the problems.
One possible solution; remove the marketing projects in question from
the scenario or from the planning scope.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.