BR-CO-20: Invoice line period (BG-26) without start and end date

What does this mean?

If an invoice line period (BG-26) is used, its start date (BT-134) or end date (BT-135) shall be filled, or both. The period in the invoice has neither.

Typical causes

The period element was created empty, e.g. because the generating system always writes it.
The dates are stated elsewhere, e.g. only in a note.

How to fix the error

State the start date (BT-134) and/or end date (BT-135) of the period, or omit the period entirely if there is none.
CII: ram:SpecifiedLineTradeSettlement/ram:BillingSpecifiedPeriod with ram:StartDateTime or ram:EndDateTime, UBL: cac:InvoiceLine/cac:InvoicePeriod with cbc:StartDate or cbc:EndDate.
Generate and validate the invoice again.

In E-Rechnungsfreund

In the invoice form, expert view ("Experte"), section "Rechnungspositionen (BG-25)" (invoice lines), fill in the fields "Zeitraum Start (BT-134)" and/or "Zeitraum Ende (BT-135)" (period start/end) of the line. If both are empty, no period is written to the XML for the line. Then validate the invoice again.

Example

Wrong

<ram:ApplicableHeaderTradeSettlement>
  ...
  <ram:BillingSpecifiedPeriod/>
  ...
</ram:ApplicableHeaderTradeSettlement>

Correct

<ram:ApplicableHeaderTradeSettlement>
  ...
  <ram:BillingSpecifiedPeriod>
    <ram:StartDateTime><udt:DateTimeString format="102">20261001</udt:DateTimeString></ram:StartDateTime>
    <ram:EndDateTime><udt:DateTimeString format="102">20261031</udt:DateTimeString></ram:EndDateTime>
  </ram:BillingSpecifiedPeriod>
  ...
</ram:ApplicableHeaderTradeSettlement>

Related validation rules

• BR-CO-03: Value added tax point date (BT-7) and tax point date code (BT-8) are mutually exclusive
• BR-CO-04: Invoiced item VAT category code (BT-151) is missing
• BR-CO-05: Document level allowance reason code (BT-98) and allowance reason (BT-97) must indicate the same type
• BR-CO-06: Document level charge reason code (BT-105) and charge reason (BT-104) must indicate the same type
• BR-CO-07: Invoice line allowance reason code (BT-140) and allowance reason (BT-139) must indicate the same type
• BR-CO-08: Invoice line charge reason code (BT-145) and charge reason (BT-144) must indicate the same type