Item &1 &2: GR to TU or Door - simple unloading not possible

What causes this issue?

Delivery item has no goods movement bin (probably a transportation
unit (TU) is intended for the goods movement) or GM will be posted to a
door bin.
Reverse unloading is not possible for complex unloaded items. You must
create manuall WT to load items/HUs again.

System Response

Delivery item must be unloaded using a warehouse task, simple unloading
not possible.

How to fix this error?

You can use the 'unload WT create' or 'unload and putaway function'.
Staging information must be available in the inbound delivery.
Or create putaway WT for the delivery.

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.