You have not specified a reorder point

What causes this issue?

On the basis of the MRP type specified, the material is to be planned
using reorder point planning with automatic calculation of the reorder
point.
However, the reorder point is recalculated only in the next forecast
run for the material; that is, if the material is planned before the
next forecast run, a reorder point of zero will be considered.

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?

Check your entry.

Error message extract from SAP system. Copyright SAP SE.