Tax category code must occur exactly once

Error FX-SCH-A-001062 Factur-X

Element 'ram:CategoryCode' must occur exactly 1 times.

Mandatory rule: As long as it is violated, the invoice is invalid and will be rejected by validators.
What is wrong

ram:CategoryCode does not occur exactly once in ram:IncludedTradeTax. The element is either missing or appears more than once.

What the rule means

The tax category code identifies the category of the tax information. The rule requires this code to be present exactly once.

Please include the tax category code exactly once

The tax information for an invoice line’s net price is missing the tax category code, or includes it more than once. You can correct this in the relevant part of the invoice.

What to do
  1. Find ram:IncludedTradeTax in the net price of the affected invoice line.
  2. Make sure ram:CategoryCode occurs exactly once inside it.
  3. Generate the invoice again and validate it again.
What it looks like
✗ Triggers the message 
<ram:IncludedTradeTax/>
✓ Correct 
<ram:IncludedTradeTax>
  <ram:CategoryCode/>
</ram:IncludedTradeTax>
Technical details

The Schematron check counts the direct ram:CategoryCode elements in ram:IncludedTradeTax and requires a count of 1.

Where the rule applies

The rule applies to ram:IncludedTradeTax within the net price of an invoice line.

Context (rule/@context)
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:IncludedSupplyChainTradeLineItem/ ram:SpecifiedLineTradeAgreement/ram:NetPriceProductTradePrice/ram:IncludedTradeTax
Test expression (assert/@test)
count(ram:CategoryCode)=1