ART-0003 - Article code is not a number.
Translation: ART-0003 - Artikelcode is geen nummer.
The article you are trying to synchronize is too long or is not alphanumeric.
Make sure that the article data in SnelStart is correctly configured. In SnelStart 12, you can convert your article data from numeric to alphanumeric and vice versa, or you can increase the size of the article codes. You can configure this in the "Type of article code" setting.