BR-24 — Missing line net amount
What it means
Each invoice line must state a net amount. This amount is quantity times price (with allowances/charges, if any) — and the invoice total is built up from the sum of all line amounts (see BR-12).
How to fix it
Check that each InvoiceLine has a LineExtensionAmount element filled
in, and that it matches the formula quantity × price (see also PEPPOL-EN16931-R120).
Example
Wrong: the LineExtensionAmount element is missing.
Correct: <cbc:LineExtensionAmount currencyID="EUR">500.00</cbc:LineExtensionAmount>.