Enter a supplier RMA number

What causes this issue?

Supplier return material authorization (RMA) is required but has not
been maintained.
In a returns purchase order, the RMA number must be maintained in order
to create a delivery.
In a returns order or returns stock transport order, this message
informs you that an RMA number is required to complete the returns
process.

System Response

A delivery cannot be created if the RMA number is not maintained in a
returns purchase order.

How to fix this error?

Maintain the RMA number in the returns purchase order.

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.