Document type & not defined for invoice verification

What causes this issue?

The error message can have the following two causes:
No document type has been configured in Customizing for transaction
&V2& that you are executing.
You have entered a document type that has not been defined for Invoice
Verification.

How to fix this error?

Check the Customizing setting in 'Document types: invoice verification'
(<DS:TRAN.OMR4>Proceed</>), or change the document type.

Error message extract from SAP system. Copyright SAP SE.