Enter a valuation type in field 'Batch'

What causes this issue?

The material you entered is subject to split valuation. but you did
not enter a valuation type. However, a valuation type is required
to enable the system to determine the valuation class and thus the
G/L accounts.

System Response

If you do not enter a valuation type, the system uses the valuation
class at the level of the valuation area.
If this message is an error message, the system was not able to
determine a valuation class for the valuation area in the
material master record.
If this message is a warning, it indicates that the system has found
a valuation class for the valuation area and will carry out the
account determination on the basis of this valuation class. The system
issues this message to warn you that this valuation class may be
different from the valuation class of the valuation type.

How to fix this error?

If you know the valuation type, specify it when entering the
reservation.
If you do not know the valuation type, check the valuation class at
the level of the valuation area in the material master record. You find
the valuation class for the valuation area (plant or company code)
in the accounting data of the material.
<DS:TRAN.MM03>Proceed</>

Error message extract from SAP system. Copyright SAP SE.