Custom Character Felling Through Map?

I know this does not have to do with scripting but I figured maybe somebody would have an idea on how to fix this problem.

So I created a custom character using a humanoid and the custom character creator plugin. I have created characters before but every so often they have this problem and I can never fix it.

The character will fall through the map until he hits his Humanoidrootpart and then he will stop falling then bounce back up and repeat the process.

I lowered the weight of everyblock this didn't solve the problem. I raised the thickness of the map. This didn't solve the problem either.

Does anyone have any idea on how to fix this. I have been having this problem for over a year now and I have never been able to find a solution.