This error can occur after migrating with Cart2Cart (C2C)
To create a product you need to define whether the product is a taxable good or not. If is, you need to define a Tax Class, otherwise it will return this error message.
If you migrated from another platform using the Cart2Cart service it is possible that C2C didn't assign the correct Tax Class to your products.
To fix this, add another column to your CSV file with the header tax_class_id and enter as the cell value "2".
Run the import again and verify afterwards within your products under Pricing > Collect tax on this product that the Tax Class is assigned.
Updated over 1 year ago