Hi Akhil,
Please try SAP note#1855612 - Initial transfer of Inbound Delivery Documents not possible.
Regarding the block message that you are getting while PGR, as Aman suggested already please check the status of the preceding PO in GTS. If its blocked or if the PO wasn't transferred to GTS you will face such issues.
Regarding Business scenario: You can use Inbound delivery for Customs declaration prior to Goods receipt, Pre-Declaration for US Import security filing and to Discharge transit procedures
- Customs declaration prior to Goods receipt can be done with PO as well but Inbound delivery can supplement more data for creation of Declarations.
- To create a pre-declaration document for US Pre ISF filing
- To discharge transit procedures- This is used to present your goods to customs while importing.
When you activate your inbound delivery for Customs, you should also enable to preceding PO document type for Customs processing.
Regards
Dhilipan