Doors opened at seven. By ten past, the queue reached the car park and none of the three phones on the gate could reach the internet.
What went wrong
The venue's network was saturated the moment the room filled with phones, and our scanning was reaching for a live connection on every scan. We had tested the app that afternoon in an empty building on a quiet network, which tested nothing.
What we did in the moment
Split the queue by surname, put two people on a printed guest list with pens, and let the third keep trying to scan. Slow, ugly, and it cleared the queue in twenty-five minutes. We recorded who came in and reconciled afterwards.
The cost
Roughly forty people left before reaching the door. We refunded every one who asked, which was fourteen. The rest we contacted with a code for the next event; nine used it.
What changed permanently
We now confirm the guest list is held on the device before doors, so scanning never depends on the venue's network. We carry a printed list as a matter of course. And we test with the room full, not the room empty.
The part that mattered most
We told people what was happening. One person walking the queue explaining the delay turned an angry crowd into a patient one. Silence is what makes a queue hostile, not waiting.