Open the transaction in your activity to see the reason. The most common ones:
Not enough balance. The purchase plus the fee was more than the balance across your accounts. Top up and try again.
Card locked. Unlock your card in the app.
Over a limit. A single purchase can be between $1 and $2,000, and your card has a spending limit of $10,000 in any 24 hours.
Negative balance. If a previous payment took your balance below zero, card payments are paused until you top up.
The merchant doesn't accept Visa.
Check your balance and card status in the app, then try again.