Steam retail Serial Number "Not available for purchase in your country"

I have a retail copy of the Crash Bandicoot N. Sane Trilogy for PC.

When I try and redeem my code, Steam issues the error message:

The product is not available for purchase in your country. The purchase is cancelled.

I have checked the product at the Steam store and the product does seem to be available in my country as I am able to purchase it through the Steam store.

Is it a problem with my serial code? Do I need to contact steam regarding this one?

You most likely bought a game key for another region and the region lock prevents you from activating it. Make sure to check if the website you bought it from indicates any sort of region lock for this key.

More info on the different region definitions can be found here.