Why is my upi id invalid?

Apple ID or UPI ID?

The latter is used in India for Financial transactions from banks to Merchants.

Based on your country of residence and country you have selected under your Apple ID --> Payment methods that you can use with your Apple ID - Apple ...

Have you a Debit/Credit card that is issued to you that is valid internationally and is from the same Country / Region as your Apple ID.

While adding funds to my Apple ID for smooth storage , why my UPI ID is coming invalid ?

whereas the same UPI Is working in other apps perfectly ..