BhajaGovinda Said:
"Hi: I want to add a card to my wallet. It’s not allowing me to. I have added that card in my other phone and it did allow me. Can you pls let me know why it’s not allowing me to add that in another phone?"
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Use a Computer:
Perform this using a computer, as it would be more user-friendly, doing so.
Refer to this Link: If you can't add cards to Wallet to use with Apple Pay - Apple Support
Contact your Bank:
If you still cannot get this to be added, then contact your financial institution (i.e. bank). Perhaps this may be seen as a scam, though that may not be the case. Let them know that this is you intending to perform this, and that all is ok to be preceded with.