Post Grid is shown as a single column, not a proper grid

Hi everybody,

So I have been trying out your Post Grid Plugin and really liked it in theory. Unfortunately i was not able to apply it in the way I expected it to.

I wanted to do a list of all projects (the issue remains also if i am using posts) in a grid with maybe 3 or 4 columns. Nevertheless, no matter how i change the plugin settings (grid item width) it always only shows me one column. Already tried with different distinct width as well as fixing it to a percentage. It still does not change the column amount present. Here is a link to the preliminary grid page: https://rendite-vergleich.org/bucherempfehlungen/

Any help is highly appreciated!

Best regards,

– sir waldo