Thanks a lot for the support! This works for me.
The browsers I have used are Chrome, IE and Edge on Windows 10 and Chrome on my Android phone.
I took 2 printscreens: the first one is the first load of the page where no gallery shows up. The second one is after a refresh of the page when everything works like it should.
This is the link to the printscreens:
https://elitefokker.be/printscreens/
So no error shows up, only a blank space on the page.
