The reason the EIWB was not posted is that the document (sale) on the basis of which the EIWB was created was not reflected in the accounting records. The fact is that the EIWB was created manually, separately from the source document, whereas the correct way is to generate the EIWB directly from the sale document itself.
How to fix it
Do not create the EIWB as a separate, standalone document. Open the relevant sale document that has already been posted and reflected in the accounting records, and create the EIWB directly from it — using the corresponding command within the sale document itself. In this case, the EIWB will automatically pull all the necessary data from the source document and will be posted correctly, since the link between the documents will be established properly.
If the sale from which you are trying to generate the EIWB has not itself been posted or reflected in the accounting records, you must first post and reflect it, and only then generate the EIWB on its basis.
Frequently Asked Questions
Why can't I just create the EIWB separately, manually?
Because when created manually, the document is not linked to the source document (sale), and the system cannot post it correctly — the link is lost, which is why the EIWB "is not reflected" in the accounting records.
What should I do if the sale has already been posted, but the EIWB still won't post?
Make sure the EIWB itself was created directly from the card of that sale, and not as a separate document — this is the key condition for correct posting.