Why is my Pay with QR transactions failing?

For transactions from Pay with QR, we request you to follow a few steps.
When the QR is active, do not close the app or navigate anywhere else and this might lead to the expiry of the generated QR code. If any transaction happens for an expired QR, this may lead to failure of the transactions.
If any money is debited, the refund will be initiated automatically and will be received in the source account by 5-7 working days (excluding bank holiday)