Your T1 declaration has been rejected with the message:
The postal code entered in the “Customs sub place” field is invalid. You can see which presentation locations are available on the Customs website:
You need to change the postal code. If the declaration constitutes a normal procedure, code NL000511 must be entered. If the declaration entails a simplified procedure, code NL000510 must be entered.
By clicking on “Re-use declaration”, you can amend the data. This is located at the bottom right of the declaration.