Popover not working

Strangely enough it all worked fine, and now it doesn’t.
I checked if it had to do with the other issue of missing a bracket in the vendor.css, but it doesn’t. So very annoying that I would have to start all over again on the bootstrap css.

Is there a cause you see why

<a href="#0" tabindex="0" role="button" class="popovers color-main-link" data-toggle="popover" data-trigger="focus" title="" data-content="text goes here" data-original-title="lovely header">lovely header</a>

    $(function() {
      $('[data-toggle="popover"]').popover();
    });
    $("[data-toggle=popover]")
      .popover({
        html: true
      });

does not work anymore?

I noticed that, if I change this code to (.popovers instead of .popover)

    $(function() {
      $('[data-toggle="popover"]').popover();
    });
    $("[data-toggle=popover]")
      **.popovers({**
        html: true
      });

the slider on the homepage (OwlCaroussel) does not work anymore. So the carroussel and the popover are related?