MRP controller can only be specified for plant

What causes this issue?

The MRP controller is set at plant level. A purchasing or sales
organization may include several plants. It is therefore not possible
to allocate one MRP controller to every one material. The same applies
to analyses that cumulate values per material across all plants.

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?

Error message extract from SAP system. Copyright SAP SE.