I refreshed my desktop app and the box saying I'm using an HTML5 suddenly got lost. Before this happened, I've refreshed a few times but it was still there. And now that I've refreshed it again, it got lost. Once it got lost, I finally got to enter the game.
It is a bit weird but maybe it was just a glitch. Cause I didn't even request this account (Lei) to be part of the HTML5 testing. It was my main account (Mina) that I volunteered to.