Hi Marianna,
Your analyse is correct:
- If there is only one trading partner in the document coming from either customer/vendor account, it is normally copied to all line items.
- If you have more than one trading partner then the system consider the document as "inter company posting" and issue an error message unless the proper check box is activate in the document type (as it is in your case).
- Trading partner is normally inherited from customer/vendor but can be manually entered if the proper check box is activate in the document type (as it is in your case but not relevant I think because the document is automatically posted).
Best regards
Th.