External nota fiscal number missing &

What causes this issue?

The external Nota Fiscal number is missing

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Please maintain the reference document number in the invoice header
or check the customizing for the used Nota Fiscal record types
<DS:DE.J_1BRTNOREFIV>invoice reference check</>.

Error message extract from SAP system. Copyright SAP SE.