How do you think I could fix this

Yea I chose speedrun mode and when I try to go through the pipe there's an invisible floor that I can't go through

I did all of the platinum challenges but after finishing defence I'm stuck in the plat zone. It might be because I don't have enough P's as I only collected 4 in some of the challenges but this shouldn't matter as stated in the rules. I would show a screenshot but the site didn't let me