Make sure that the OZ can be found in column A and that this is structured in ascending order and that the PosArt has been defined correctly.
With the installation of "GAEB-Online 2023", a sample file is installed on your computer. You can find this sample file via Start | Program group "GAEB-Online 2023" there in the Import Sample folderor as a link named "GAEB-Online - Link to Import Sample" on your desktop. With this file you can test the import or you can use this file as a template for your Excel data.