Is NOL's queue random or is it me?

I was trying to buy tickets for Stray Kids 6th fan meeting. I get that a lot of people wanted to go so everyone's chances weren't great but I was trying since the FANS presale (so 3 separate times) and was always waiting on the website at leat half an hour earlier. As soon as the button was available, I would click but it wouldn't register and it would take 2 or even 3 clicks and then there were always around 35k people around me. Was I doing something wrong? Should I have done something different? It was my first time so I'd like to know.