Continuously getting error Card not added..Try again
iPhone X, iOS 15
Question marked as
Try first to optimize the range of the mobile network, see this Apple article:
If you see No Service or Searching on your iPhone or iPad
If you see No Service or Searching on your iPhone or iPad - Apple Support
Then try again -> Sign in to your Apple ID account page and edit your Apple ID details.
On the Sidebar click Payment methods -> then tap Payments Methods and tap Manage payment method.
Or -> Change, add or remove Apple ID payment methods
Change, add or remove Apple ID payment methods – Apple Support (UK)