Hi guys,

when I setup a grid in bootstrap 4 everything works fine. As soon as I add Cards, the website only displays white. No error or anything. When I remove the card or card columns the website works again.
The page that doesn't work: www.mn-trade.com/index.html
The same page as php page: www.mn-trade.com/index.php

I have the site without using any cards, so just the header image and the columns which works fine until I add a Card: www.mn-trade.com/in.html