Are you seeing messages of this kind there:

The following applies:

The error is also shown in the log, for example under "SKU 1234 not generated", or "0:„sku“

In the catalogue, it is defined in the first place from which source the SKU should be generated. We distinguish here between a "Parent SKU" and a "Variation SKU". The chosen source should refer to a data row that exists uniquely. It is therefore not possible to assign the same SKU again for different articles.

As an example, one could use the "Article ID" as well as the "Variation ID". Both IDs are assigned by the system when creating the article and exist only once.

However, it could happen that the article export has taken place and the export has failed due to missing information in the catalogue. The SKU was nevertheless written and is now visible in the variation under the "Availability" tab. At the next export, the system would again try to create an SKU from the sources selected in the catalogue. Since this SKU already exists, the following error occurs:

Duplicate entry. Combination of the fields variationId, marketId and accountId must be unique

SKU 1234 not generated

For this reason, it is necessary to add an alternative data field in the catalogue. This would then look as follows:
 

Attention: it is absolutely necessary that when adding the additional source, the (+) button "Add alternative data field" is used. Please DO NOT use the option "Add data field", as this will create your SKUs twice and will not contribute to the desired solution!

This adds a 2nd source. At the next export, the 1st source will be accessed first. Since an SKU already exists in this source, the 2nd source is ignored. If no SKU exists in the 1st source, a new SKU will be created using the 2nd source.

An example of a correct mapping: