In Photos I can not buy book. Problem with address and ZIP

Go back and re-enter all of your billing data. Delete the old data and then re-enter. If the full ZIP code is asked for enter the full ZIP code: XXXXX-XXXX.

See if that will jumpstart the purchase process.

If that fails contact Apple at the appropriate phone number from this Apple document: Contact Apple for support and service - Apple Support

Are you trying to buy from the Netherlands store, or the US store? You can't purchase from the US store if you're in the Netherlands.

In the Photos preferences verify that you are using the local Print Products store

LN

To reinforce KiltedTim's response:

Make sure you've selected the correct Print Product Store.

You are welcome

LN