I filled ours out online with no problem. I also filled out the paper form on the plane. We arrived at 3pm on a Saturday and the immigration hall was as busy as I’ve seen it. We used Club MoBay for arrival and because we had the paper forms filled out we were able to skip the kiosks and I’m sure saved a lot of time. Until they finish working out the bugs in the online system I recommend also filling out the paper form.