Dropdown menu's do not work in MS EDGE

Expected behavior

The navbar and breadcrumbs should show a dropdown

Actual behavior

In Microsoft Edge the dropdown functions are not supported. If I click on the navbar (dropdown) items or de breadcrumbs (dropdown) they do not show up.

Resources (screenshots, code snippets etc.)

See https://stargroup.nl/over-ons/ons-team/lau for the situation.

Code snippet:

 <nav aria-label="breadcrumb">
        <ol class="breadcrumb">
            <li class="breadcrumb-item"><a href="/over-ons/">Over ons</a></li>
            <li class="breadcrumb-item"><a href="/over-ons/ons-team/">Ons team</a></li>
            <li class="breadcrumb-item">
                <a class="dropdown-toggle" href="#" role="button" id="dropdownMenuLink" data-toggle="dropdown"
                    aria-haspopup="true" aria-expanded="false">
                    Lau
                </a>
                <div class="dropdown-menu mt-3">
                    <a class="dropdown-item" href="/over-ons/ons-team/danny/">Danny Hensen</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/dirk-jan/">Dirk Jan Plate</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/gerard/">Gerard van Manen</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/gosse/">Gosse van Veldhuizen</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/frank/">Frank van Elten</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/emily/">Emily Beekman</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/colette/">Colette Bakker - van de Kuit</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/timon/">Timon Schumacher</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/lisa/">Lisa van Veen</a>
                    <a class="dropdown-item" href="/over-ons/ons-team/courtney/">Courtney Cooke</a>
                    <a class="dropdown-item active" href="/over-ons/ons-team/lau/">Lau Dijksterhuis</a>
                </div>
            </li>
        </ol>
    </nav>

Please help