Unit of meas. & of material & & not valid for pool &

What causes this issue?

The unit of measure of the material differs from that of the pool.

System Response

For the "quantity LIFO" procedure, all materials included in a pool
must have the unit of measurement of the pool as base unit or
alternative unit.

How to fix this error?

Change the pool allocation in the master record of material &V3&.
Alternatively, enter the unit of measurement of the pool in the master
record of this material.

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.