Apple Wallet is not working on my iPhone 11 Pro Max

You are not addressing Apple here. This is a user to user support forum and a place for users to help users. For anyone to be able to diagnose the problem, you would need to provide a lot more detailed information here besides "is not working", and "shows an error", when you do not even indicate what the exact error is.

If you would rather speak with Apple about the error, use the Support link at the bottom left of the page.

What is the exact error you receive when you try to add a card to your Wallet?