Stor.type & whse no. & not maintained for ref. mat. &

What causes this issue?

The reference material &V3& does not yet have any warehouse management
data at the level of storage type &V1& warehouse number &V2&.

How to fix this error?

INCLUDE NA_EINGABE_PRUEFEN
If your entry is correct, create the material master record for storage
type &V1& warehouse number &V2&.

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.