Thank you - but I already have Yoast installed ... :-/
Actually I was thinking if perhaps that is the problem: That Yoast somehow "overwrites" the description given in the Lay Options? Is that a thing?? While Yoast allows me to edit the snippet for each project-page, I don't find the possibility to edit the snippet for the "Home"-page (I can change the snippet for the category-page, but although this also functions as my "Home"-page, the url is different).
Can you tell me where to change the snippet/meta for the Homepage with Yoast? Or is there no point in it and the problem is a different one?