Specify item category for non-stock items

What causes this issue?

You want to allocate non-stock materials that are externally procured to
a general task list, an equipment task list or a task list for
functional locations. You can enter non-stock items either with or
without a material master. However, for these items you must maintain
purchasing data in the bill of material and provide the item category
<LB>N</>.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Configure your system accordingly and assign the item category <LB>N</>
to the standard BOM usage for <ZK>Plant Maintenance</>.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.