Diagnosis
You are trying to assign an HU with different material items to ashipment. There are either several materials or several different stockcategories for one material in the handling unit. The system cannotprocess such a handling unit.
Exception: Handling Units with batches have several material items andcan still be processed.

Procedure
Remove the handling unit from the list of HUs that are to be assigendto the shipment. Then, change the handling unit so that it onlycontains one material item.