This payment processor is the most widely used in gaming in the UK, but it drives me mad from time to time as it can be very sensitive.
A small number of the 15 players who used the test link earlier today, subsequently had a failed transaction at 9pm. If those players had completed their failed transaction before the final seat was allocated this evening, then they will be on the player list for Cardiff and we will send them a fresh payment link in a couple of days when their card does not trip the "multiple use within 24 hours" flag.
I have all of the timings surrounding this so it is extremely easy to work out.
....and we need some bigger venues.