Changing the client dependency will affect future activation rules. &1

What causes this issue?

Changing the Customizing Scope will change the rules for the activation
of Feature Toggles.
In case the 'System Wide' attribute is switched on, the activation of
client/user restrictions is not allowed.
(This applies for all system wide features when release status <> 'D'
(Development)
When switching on the 'System Wide' attribute for an already active
toggle, all existing customizing restrictions will be ignored.

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

System Response

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.