schemeID for the URI identifier

Error FX-SCH-A-000906 Factur-X

Attribute '@schemeID' is required in this context.

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

The schemeID attribute is missing from the ram:URIID element within ram:URIUniversalCommunication.

What the rule means

The schemeID attribute identifies the scheme of the URI identifier. Without this attribute, the identifier scheme is not specified.

Please add `schemeID` to `ram:URIID`

No schemeID attribute is provided on ram:URIID for electronic communication. You can add this attribute to the URI identifier.

What to do
  1. Locate ram:URIID within ram:URIUniversalCommunication of ram:InvoicerTradeParty.
  2. Add the schemeID attribute to that ram:URIID.
  3. Generate the invoice again and validate it once more.
What it looks like
✗ Triggers the message 
<ram:URIUniversalCommunication>
  <ram:URIID>value</ram:URIID>
</ram:URIUniversalCommunication>
✓ Correct 
<ram:URIUniversalCommunication>
  <ram:URIID schemeID="value">value</ram:URIID>
</ram:URIUniversalCommunication>
Technical details

The test condition directly checks whether the schemeID attribute is present on the context node.

Where the rule applies

The rule applies to the schemeID attribute of ram:URIID within ram:URIUniversalCommunication of ram:InvoicerTradeParty.

Context (rule/@context)
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement/ ram:InvoicerTradeParty/ram:URIUniversalCommunication/ram:URIID
Test expression (assert/@test)
@schemeID