What does DMS656AA mean?

The codebook sets at DMS656AA the wording GEGEVEN IS VERPLICHT OBV TWEE ANDERE GEGEVENS EN CODELIJSTEN. That line names the element or the situation, not the cause on your file.

Does the code say why my declaration is wrong?

No. The code names the element or the reason class. The location in the message and the master data say why it fails on this file.

Do I get an MRN with this error?

No. This is an acceptance-blocking error. For as long as the named element is wrong, the declaration is not accepted and there is no MRN.

May I translate or shorten the official text?

Not as a source. Customs publishes the wording in Dutch. A translation in software is a display, not a second official text.

A99 · Blocks acceptance

DMS656AA

Official wording from the codebook

GEGEVEN IS VERPLICHT OBV TWEE ANDERE GEGEVENS EN CODELIJSTEN

What does the codebook say for this code?

The official wording is: GEGEVEN IS VERPLICHT OBV TWEE ANDERE GEGEVENS EN CODELIJSTEN. That text comes straight from the Dutch codebook. We do not translate or shorten it here. The legal note in the same table is: Voor twee gegevens worden de bijbehorende codelijsten geraadpleegd. Het wel of niet voorkomen van de opgegeven waarden in de codelijsten verplicht het opgegeven van het gegeven vermeld in het afwijzingsbericht omdat dit gegeven ontbreekt. The code names the element or the situation. It does not say why that element is wrong on your file. Two consignments with DMS656AA can need a different correction.

Where does this code come from?

DMS656AA sits in table A99 FOUTCD.AANGIFTE of the Codeboek Douane, part UCC declaration handling. That is the list DMS uses when it returns a declaration. AGS or Sagitta numbers from the previous system do not belong here. A German or Belgian code does not either. Source: Codeboek Douane, part UCC declaration handling, table A99 FOUTCD.AANGIFTE, edition 2026-08-29.

Does this error block acceptance?

Table A99 marks DMS656AA as an acceptance-blocking error. The declaration is not accepted for as long as this element is wrong. There is no MRN. Correct the named field and file again.

How do you find the real cause?

Start from the location in the message, not from a list of fixed fixes. Put the named field next to the source document and the master data. Do not guess a cause from DMS656AA alone. The official list changes. This page follows the edition of 2026-08-29. A screenshot from last year can carry different wording. The Nationale Helpdesk Douane points to the codebook, not to a vendor list.