Problem with My Generate Premium

I have bought the generate press premium which allows me to do more stuff. It is updated and everything else is fine but it don't let me change the theme background or other images in the theme.

When I push "upload" button nothing happens. Only thing what happens is that in the end of my URL comes # mark. Nothing else. I have tried to fix this with the details I can find from support topics but nothing works.

Can you please help with this?

Thanks!