Where does the space between two sections on Mobile come from?

Hey guys,

while creating and revising my website I found some errors, which I can’t really solve by myself, so I need your help.

Between my herosection and the following section, when I open the website on my iPhone, there is a big white gap. I have tried a lot to remove it and I just don’t know what the problem is.

Here is my read only link:

And here is a screenshot of the problem:

And here is the live page:

I would be super happy if someone could help me!