E-invoice error explained
As soon as a line, allowance or charge uses one of the VAT categories S, Z, E, AE, K, G, L or M, the seller must be identifiable for tax purposes.
As soon as a line, allowance or charge uses one of the VAT categories S, Z, E, AE, K, G, L or M, the seller must be identifiable for tax purposes. One of three is enough: VAT ID (BT-31), tax number (BT-32) or a tax representative (BG-11). The rule does not apply to category O (not subject to VAT). L and M are special categories for the Canary Islands and for Ceuta and Melilla.
If the tax codes S, Z, E, AE, K, G, L or M are used in an invoice, at least one of the elements "Seller VAT identifier" (BT-31), "Seller tax registration identifier" (BT-32) or "SELLER TAX REPRESENTATIVE PARTY" (BG-11) must be transmitted.
Source: KoSIT configuration XRechnung 3.0.2 (31 Jan 2026).
Add ram:SpecifiedTaxRegistration inside ram:SellerTradeParty. For the VAT ID use ram:ID schemeID="VA" (for example DE123456789), for the German tax number schemeID="FC" (for example 201/123/45678). Both may be present. The block goes at the end of the seller party, after ram:PostalTradeAddress and ram:URIUniversalCommunication.
Wrong (CII)
<ram:SellerTradeParty>
<ram:Name>Muster GmbH</ram:Name>
<ram:PostalTradeAddress>...</ram:PostalTradeAddress>
<ram:SpecifiedTaxRegistration>
<ram:ID schemeID="VAT">DE123456789</ram:ID>
</ram:SpecifiedTaxRegistration>
</ram:SellerTradeParty>Right (CII)
<ram:SellerTradeParty>
<ram:Name>Muster GmbH</ram:Name>
<ram:PostalTradeAddress>...</ram:PostalTradeAddress>
<ram:SpecifiedTaxRegistration>
<ram:ID schemeID="VA">DE123456789</ram:ID>
</ram:SpecifiedTaxRegistration>
<ram:SpecifiedTaxRegistration>
<ram:ID schemeID="FC">201/123/45678</ram:ID>
</ram:SpecifiedTaxRegistration>
</ram:SellerTradeParty>Sales / Project Operations: Sales and Project Operations have no e-invoice output out of the box. In the WBS Invoice Accelerator for Dynamics 365 both numbers are on the brand profile: VAT ID and Tax number. One of them is enough.
Business Central: Enter the VAT ID in the VAT Registration No. field on the Company Information page.
Finance: Under Legal entities, Foreign trade and logistics FastTab, the tax registration number goes in the VAT exempt number export field.
Check your invoice for free. The validator shows every finding with an explanation and its location in the XML.