Did you try to pay with your card and the purchase was declined? This can happen for a few simple reasons:
Insufficient balance on the card
The purchase amount exceeded the card's daily limit
Temporary error with the merchant's terminal
What to do:
Check your balance in the app.
Adjust (if necessary) the daily spending limit in “Card Settings” in the app.
Try paying again after a few minutes.
If it fails twice at the same location, the terminal might not be able to read the card (try inserting instead of tapping).