What does NCTS 90 mean?

The codebook sets at NCTS 90 the wording ONBEKENDE MRN. 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.

Is this a DMS error code?

No. This is an NCTS message from the Codeboek Sagitta, part Transit. DMS uses table A99. The two lists are not interchangeable.

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.

NCTS 049

NCTS 90

Official wording from the codebook

ONBEKENDE MRN

What does the codebook say for this code?

The official wording is: ONBEKENDE MRN. That text comes straight from the Dutch codebook. We do not translate or shorten it here. The legal note in the same table is: Het MRN van de ontvangen FMS is niet gekend, terwijl een gekende MRN werd verwacht. Dit fouttype kan niet voorkomen in een AAR (C_AAR_SND). The code names the element or the situation. It does not say why that element is wrong on your file. Two consignments with NCTS 90 can need a different correction.

Where does this code come from?

NCTS 90 is a functional error code from table 049 of the Codeboek Sagitta, part Transit. That is the Dutch source for NCTS error messages (DVA). These codes are about the message: a reference is missing, a value is not allowed in that place, or the MRN is unknown. Source: Codeboek Sagitta, part Transit, table 049 FUNCT. FOUTCODE, edition 2026-08-29.

What kind of message is this?

NCTS error codes from the Transit codebook are not DMS A99 codes. A functional error (table 049) points at the message itself. An AAR or ATR rejection reason points at why arrival or transit was refused. There is no transit discharge for as long as that message is open. Read the official wording and the message type (arrival or departure) before you send 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 NCTS 90 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.