I am unable to add card in my Apple Wallet

Contact the banks Apple Pay or fraud teams and ask why. They will probably tell you everything is fine and to talk to Apple. Apple won’t be able to tell you anything for various reasons and I’ll explain how Apple cannot tell you anything because Apple has no access to your banks information or the Payment Network Operator (Visa, Mastercard, etc). All Apple’s information is anonymous and not tied to your identity or account.

You may have to give your card issuer a call then. Not every bank supports Apple Pay

Have you contacted the card issuers support team? If so, what did they say?

What country are you in and what country is the bank in that issued the card?

Is it your Apple Card MasterCard ?

What is the error message you receive when you try to add a card?