Entry & not defined in table T340D

What causes this issue?

Via the interface inventory management/warehouse management, the system
has found a <GL:warehouse_number>warehouse number</> whose
characteristics have not been maintained.

System Response

The system cannot generate a <GL:quant>quant</> in the warehouse
number.

How to fix this error?

INCLUDE NA_NIX_MEHR
INCLUDE NA_SYSADMIN1
If you are authorized to do so, do you want to
<DS:TRAN.OML2>check</> the allocation plant - warehouse number?
<DS:TRAN.OML1>check</> the warehouse number definition?

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.