Are you trying to close a bill above 400 EUR for a Spanish customer, but you keep getting the error
Invalid tax identifier?
Don't worry, this is an easy fix!
It happens because the Tax identifier or NIF is missing from the customer profile.
Navigate to the customer's profile tab and fill in the Tax identifier field with the client's NIF (composed of eight numbers and one capital letter).
That's it! You can learn more about Spanish fiscal integration by clicking on the link below.