XV-MY-29
Each line needs its tax amount (cac:TaxTotal/cbc:TaxAmount) and tax type (cac:TaxSubtotal/cac:TaxCategory/cbc:ID), also when no tax is charged; line … lacks them.
error: the document is invalid
What the rule checks
As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.
Context
/*/cac:InvoiceLine
Test
cac:TaxTotal/cbc:TaxAmount and cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory/cbc:ID
Checked with MyInvois e-Invoice