It is the most demoralising version of this whole process. The calendar finally shows a green date. You click it, start entering details, and the system tells you the slot is no longer available.
You did nothing wrong. Here is what happened.
Nothing was ever reserved for you
The mental model most people bring is a concert ticket: click it, and it is held for a few minutes while you check out.
Booking does not work that way. The calendar shows what was free at the moment the page rendered, and the appointment goes to whoever completes the booking, not whoever starts it. There is no hold, no queue position, no basket.
So every second between seeing the date and finishing the form is a second the appointment is still on offer to everybody else looking at the same calendar.
Why this bites so hard on busy routes
Appointments arrive in batches. When one lands, it is not just you who sees it — it is everyone refreshing that route, plus every automated watcher pointed at it. A batch on a contested route can be gone in minutes.
Against that clock, the ordinary friction of filling in a form is decisive. Looking up a passport number. Checking the spelling of a name against the document. Deciding between two visa categories. Any one of them is enough.
This is also why the problem gets worse as the group grows: four applicants’ details take longer to enter than one, against exactly the same window. Group bookings need their own preparation for that reason.
What actually helps
Have everything assembled before you start. Passport numbers, dates, spellings exactly as printed, the application reference. Not “findable” — open, in front of you. The booking window is not the time to go looking.
Decide your category in advance. Choosing between two plausible categories mid-booking is one of the most common ways people lose a batch, and it is a decision that should never be made under time pressure anyway — the wrong category gets the application refused later.
Decide your centre in advance too. If your route has two, know which you will take before anything appears.
Do not reload after a failure. The instinct is to refresh hard and try again. That is how a bad afternoon becomes a rate limit on your account — and then you cannot see the next batch at all.
Be ready for the confirmation code. Since 2026 a one-time code arrives at the confirmation step and has a short life. If it lands while your phone is elsewhere, the booking fails at the last step. What changed and why.
The uncomfortable arithmetic
Even with everything prepared, a person is racing software.
Automated watchers detect a release the moment it appears and submit immediately. A human has to notice, open the site, sign in, and type. On a window measured in minutes, that gap is usually the whole contest.
That is not an argument for despair — plenty of appointments are booked by people at keyboards. It is an argument for being honest about what you are up against, and for not concluding that losing three batches in a row means something is wrong with you.
What makes it worse
- Refreshing furiously after losing one. The single most reliable way to turn a near miss into being locked out.
- Starting a booking without the details to finish it. Guaranteed to lose anything contested, and it also blocks you from trying properly.
- Opening several tabs on the same account. It does not multiply your chances and it is a good way to trip the burst limits.
- Assuming the slot was fake. It was real. Someone else finished first.
What we do about it
We watch continuously and submit at the moment of detection rather than after it, which is the only part of this a person cannot reasonably do by hand. Your details are prepared in advance, so nothing is being looked up while the clock runs.
Even then, we lose batches. Several applicants can be racing for the same appointment and only one gets it — that is the nature of the thing, and anyone promising otherwise is describing a system that does not exist.