HU-managed storage location (&1/&2) is not supported

What causes this issue?

Handling unit (HU) managed storage locations are not allowed to be
receiving storage locations in the A&D subcontracting solution.
Therefore the following restrictions are valid:
If there is an external (subcontracting) operation in the refurbishment
order, it is not allowed to use HU-managed storage location in the 'To'
field of the order header.
If the component is assigned to a subcontracting operation and has
material provision indicator 'X' ('Rework Material from Subcontractor'),
it is not allowed to use HU-managed storage location for the component.
If the component is assigned to a subcontracting operation and has
material provision indicator 'S' ('Rework Material '), and there is no
component with material provision indicator 'X' assigned to this
operation, it is not allowed to use HU-managed storage location for the
component.

System Response

Error message is displayed and the order cannot be saved.

How to fix this error?

Use a different storage location without handling unit management in the
described scenarios.

Procedure for System Administrators

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.