Exactly one issuer-assigned contract reference is required

Error FX-SCH-A-000430 Factur-X

Element 'ram:IssuerAssignedID' 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:IssuerAssignedID does not occur exactly once in ram:ContractReferencedDocument. The element is either missing or occurs more than once.

What the rule means

ram:IssuerAssignedID contains the identifier assigned by the issuer to the referenced contract. The rule requires exactly one such identifier.

Please provide exactly one identifier for the referenced contract

The contract document does not contain exactly one ram:IssuerAssignedID. You can adjust the number of contract identifiers.

What to do
  1. Find the referenced contract document ram:ContractReferencedDocument.
  2. Make sure it contains exactly one ram:IssuerAssignedID.
  3. Generate the invoice again and check it again.
What it looks like
✗ Triggers the message 
<ram:ContractReferencedDocument/>
✓ Correct 
<ram:ContractReferencedDocument>
  <ram:IssuerAssignedID/>
</ram:ContractReferencedDocument>
Technical details

The test counts the direct ram:IssuerAssignedID elements in ram:ContractReferencedDocument and requires a count of 1.

Where the rule applies

The rule applies to the referenced contract document ram:ContractReferencedDocument in the agreement between seller and buyer.

Context (rule/@context)
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement/ ram:ContractReferencedDocument
Test expression (assert/@test)
count(ram:IssuerAssignedID)=1