For popular events, a large number of users set up alerts. When a ticket listing is accepted onto the marketplace, alerts are automatically sent to everyone at the same time—meaning lots of users may try to buy the same tickets at once. The lucky first person to click buy will put a hold on that ticket while they complete check out, meaning every single second counts - but network delays can mean someone gets there faster than you even if you appear to be instant.
We understand how frustrating it can be to miss out. Many people ask if touts and bots are snapping up tickets, but rest assured, we have robust security measures in place to deter this. We are also continually developing and investing in such systems.
As the event date approaches, more tickets usually become available, increasing your chances of securing one. Keep checking back!