SAP Message VHUPD222 - The handling unit cannot be assigned to delivery &1

Diagnosis
You wish to assign a delivery to an HU. However, the document (order/purchase order that is assigned to the HU does not match the documentthat is used as the preceding document for this delivery.

Procedure
Select the HU and choose Change HU Reference. Enter thepreceding document of the delivery or the delivery itself in thedialog box and choose ENTER.
After you have refreshed the list, you can include the HU that is nowassigned to the correct document in the delivery.

554309VL10HU: Error message VHUPD222