ram:URIID required in email communication

Error FX-SCH-A-000818 Factur-X

Element 'ram:URIID' 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

The ram:URIID element is missing from ram:EmailURIUniversalCommunication. This element must occur there exactly once.

What the rule means

ram:URIID contains the value for the contact’s email communication. The rule requires exactly one such element.

Please add the delivery recipient’s email address

The contact’s email communication is missing ram:URIID. Add this element exactly once.

What to do
  1. Locate ram:DefinedTradeContact under ram:ShipToTradeParty.
  2. Add exactly one ram:URIID element inside ram:EmailURIUniversalCommunication.
  3. Regenerate the invoice and validate it again.
What it looks like
✗ Triggers the message 
<ram:EmailURIUniversalCommunication/>
✓ Correct 
<ram:EmailURIUniversalCommunication>
  <ram:URIID>contact@example.com</ram:URIID>
</ram:EmailURIUniversalCommunication>
Technical details

The check counts the direct child elements ram:URIID of ram:EmailURIUniversalCommunication and requires exactly one.

Where the rule applies

The rule applies to ram:EmailURIUniversalCommunication within the ram:DefinedTradeContact of the delivery recipient ram:ShipToTradeParty.

Context (rule/@context)
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeDelivery/ ram:ShipToTradeParty/ram:DefinedTradeContact/ram:EmailURIUniversalCommunication
Test expression (assert/@test)
count(ram:URIID)=1