Managed to select all my flights and get through to the payment page and then this happened…does this mean it’s a phone call booking now?
This is an excerpt from an article written by David Boyd in 2018 titled "How to get around Qantas.com error codes". Can't remember where I got it from but I think it answers your question:
Error code: #15079-421 — Unable to confirm selected flights
This happens every single day with Qantas. Customers have gone through the whole process of making a booking—searched, selected seats, punched in your passenger information and payment details and hit submit–but been held up at the final stage with an error that reads:
“We are unable to confirm your selected flights. Select ‘Start over’ and choose alternative flights.”
The frustration with the
15079-421 error is that those flights
are available, even though the website says differently. Or if you're booking a Classic Rewards seat in any travel class, the points seat is
not actually available to book even the website says the seat is available.
It tends to happen a lot on international flights when a user wants to spend their Qantas points with a partner airline.
One Qantas customer tried this on a flight to Germany with Emirates and was met with the same error code. But it will happen on QF flights too. Credit Card Compare team members have hit this error many times when making bookings.
Solution
There’s no online fix for this one. Instead, jump on the phone and walk the service agent through the steps you took when you made the booking.
One customer did just that and had the agent reproduce the same booking error. The result was a booked flight using their reward points over the phone without incurring any extra charge for the phone booking. Negative outcomes also happen where no points can be made.