Hi ​@Dima Kors – thanks for posting! Is it possible that the error is because the CSV columns do not correspond with the fields already implemented in Klaviyo? I noticed that the product columns listed on the bottom part of the screenshot say Item ID whereas the CSV column is product_ID. I would check this and see if that’s the problem!

Hi ​@Dima Kors ! 

Typically this happens when the product ID automatically converts to scientific notation within your file. For example: 

I would suggest checking your file to ensure this didn’t happen. If it did, here is a guide you can follow that may be helpful to prevent this from happening: https://support.ordoro.com/how-to-avoid-the-annoyance-of-numbers-getting-truncated-in-excel-spreadsheets/

Let me know if that is not the case and I will be happy to look into this further!