Invoice generated without Nota Fiscal! NF type missing in header

What causes this issue?

You have not entered a Nota Fiscal type in the invoice header. The
invoice is generated without a Nota Fiscal.

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?

If you do not require a Nota Fiscal, press "Continue". If you do want a
Nota Fiscal to be generated, enter the Nota Fiscal type in the header
data.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.