I have updated the volleybal website http://www.wsvvolleybal.nl
from joomla 3.6.2 --> 3.6.4 and now is the website dead. On this moment I remember that I had this problem before and it has something to do with a menu item which was opening a pdf or something like that.
If I choose another template like protostar, than I see the content!
Nico van de Kamp