Product Sku in csv

I have a csv file that looks something like this:

product_sku,make,model,engine
555,askam,superTL,123
122,abarth,sergeant,898

and so on…

Problem is when I import this csv, I get this message back:

Ymm CSV file has been imported.

Row #1 was not imported. The product with SKU or ID “123” does not exist.
Row #2 was not imported. The product with SKU or ID “456” does not exist.
Row #3 was not imported. The product with SKU or ID “789” does not exist.
Row #5 was not imported. The product with SKU or ID “33” does not exist.

am I doing anything wrong?