after transfering to a knew phone (5se 2020) why can

I have just transferred data to a new 5se 2020 and everything went well. However my only problem is with Apple Pay. I used Apple Pay on the old phone but when I double tap to bring up wallet it is inviting me to 'get started with Apple Pay'. Then 'ADD' and then 'continue' and there on the screen are my two cards showing with a blue tick beside both which means they have been selected. So far so good! Then I tap continue which takes me to an 'Add Card' screen to verify the card details. The card details are greyed out and the message is 'Add This Card to Wallet Later'.

Please can someone explain why I can't add the card to wallet now?

Many thanks.