Regarding the issue with entering the product code, please check the following:
■ Ensure that there are no typos in the entered "Product Code."
■ Confirm that the "Product Code" is not expired.
Please be aware that if maintenance or issues occur on the PlayStation Network, you might not be able to enter the product code. For information on PlayStation Network maintenance and issues, please visit the following link (you will be redirected to the Sony Interactive Entertainment website): https://www.playstation.com/en-hk/support/?country-selector=true
■ Verify that the country or region of the game matches the country or region of your PlayStation Network account.
If you attempt to input a "Product Code" intended for use within Japan using a "Sony Entertainment Network Account" registered in a different country or region, you may not be able to use the "Product Code."
If they do not match, try setting the country or region of your "Sony Entertainment Network Account" to Japan and then attempt to re-enter the product code.