This error is the result of an missing documentation for invoices of over €20,000. If the Invoice value of an Import Customs Declaration is equal to or higher than €20,000.00 then a valuation statement needs to be completed for Revenue.
In Declaron, you will need to navigate to the the "Commerical Details" section of your declaration. Once there, you will need to select the "Yes" tick box to the question "Does this declaration require a valuation statement?" Four subsequent valuation questions (also called valuation indicators) must be completed for every import consignment with a value in excess of €20,000, except where the import is not commercial (other scenarios may exist so check with Revenue if unsure).
If you have a Long-term declaration form (G563a) please upload it to this declaration using the documents button as well as answering Yes to this question.