HSBC Hopper international flight payment issue

Hi Guys, I have been trying to book flights via HSBC hopper using my TravelOne card for international trip to Bali using AirAsia flight (checked that there are tickets using Skyscanner). When I complete the entire booking process and when the payment is done, the booking gets cancelled and mentions that they have an issue in the backend. I called their customer care, their agent is mentioning that the flight no longer is available for booking. When I checked via skyscanner, the flight still exists. Has anyone faced the same issue and whether it is only with AirAsia or have you guys faced it with any other airline too?

If anyone knows how to fix this, that also works