What it means
Within each header trade agreement, the check counts ram:BuyerTradeParty/ram:DefinedTradeContact elements. Zero or one passes this rule. Repeated blocks count separately even if their details are identical.
Why it matters
The CII structure provides at most one buyer contact block here. This rule limits the number of blocks, not the contact details they contain.
How to fix it
Check the buyer contact details on your invoice and choose the appropriate contact. Keep the relevant details in one ram:DefinedTradeContact under ram:BuyerTradeParty and remove the extra contact blocks. If you are unsure which contact to use, ask your buyer, then export and recheck your file.
Once the file is corrected, check it again for free: Validate an invoice against EN 16931
Or fix the invoice in a form and download the corrected file, for 1 credit: Fix a rejected e-invoice
The rule as published
DefinedTradeContact of BuyerTradeParty shall exist maximum once Where this rule applies
| Rule set | Version |
|---|---|
| EN 16931 (CII) | 1.3.17 |
| XRechnung 3.0 (CII) | 3.0.2 |
| NLCIUS (CII) | 1.0.3.13 |
| France CTC (CII) | 1.4.0-04 |
Check your file
Drop your e-invoice to see whether CII-SR-456 still fails, and which other rules do.
Related rules
- CII-SR-457 Give the tender or lot reference only once
- CII-SR-458 Give the invoiced object identifier only once
- CII-SR-459 Give the seller's electronic address only once
- CII-SR-460 Give the buyer's electronic address only once
- CII-SR-461 Give the VAT point date only once
- CII-SR-462 Use a consistent VAT point date code