I've recently set up a PayPal Pro account so that we can use the PayPal Direct UK payment option for our shop.
I put all the relevant details in the payment module on opencart i.e.
Vendor
User
Password
Partner ID
Then I use the payment option in test mode and it works fine.
I then change it to the live mode and try process a purchase using Sandbox debit card test details that I have and the order processes without any issue.
BUT
As soon as I put it in live mode and I try and process an order with a real card I get the following:
Error: A match of the Payment Address City, State, and Postal Code failed. Please try again.
This also happens when any of my customers try purchase using the Paypal Direct UK payment method on Opencart.

Please can someone advise what the issue could be?
Thanks in advance.
Jo