Taxonomy Menu funktioniert nicht (findet eine Menge an Klassen nicht)

Habe D8 firsch installiert und auf den ersten Blcik scheint alles zu funktionieren.

Taxonomie eingereichtet und Modul Menue Taxonomie installiert.

Beim einrichten eines Taxonomie Menüs kommt aber folgende Fehlermeldung:

Auf der Website ist ein unvorhergesehener Fehler aufgetreten. Bitte versuchen Sie es später nochmal.

Symfony\Component\Routing\Exception\RouteNotFoundException: Route "entity.taxonomy_menu.edit_form" does not exist. in Drupal\Core\Routing\RouteProvider->getRouteByName() (line 191 of core/lib/Drupal/Core/Routing/RouteProvider.php).
Drupal\Core\Routing\UrlGenerator->getRoute('entity.taxonomy_menu.edit_form')
Drupal\Core\Routing\UrlGenerator->generateFromRoute('entity.taxonomy_menu.edit_form', Array, Array, 1)
Drupal\Core\Render\MetadataBubblingUrlGenerator->generateFromRoute('entity.taxonomy_menu.edit_form', Array, Array, 1)
Drupal\Core\Url->toString(1)
Drupal\Core\Utility\LinkGenerator->generate(Object, Object)
Drupal\Core\Render\Element\Link::preRenderLink(Array)
call_user_func(Array, Array)
Drupal\Core\Render\Renderer->doRender(Array, )
Drupal\Core\Render\Renderer->render(Array)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1)
__TwigTemplate_274fa538b9e9b38862d70154a72f2e7561f261e17bebf268f9fe6142ca6b00df->doDisplay(Array, Array)
Twig_Template->displayWithErrorHandling(Array, Array)
Twig_Template->display(Array)
Twig_Template->render(Array)
twig_render_template('core/themes/classy/templates/navigation/links.html.twig', Array)
Drupal\Core\Theme\ThemeManager->render('links__dropbutton__operations', Array)
Drupal\Core\Render\Renderer->doRender(Array, )
Drupal\Core\Render\Renderer->render(Array)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1)
__TwigTemplate_a32454059273c52fefadf1027c4ddecaf3c46d340629f29223dc209fad082165->doDisplay(Array, Array)
Twig_Template->displayWithErrorHandling(Array, Array)
Twig_Template->display(Array)
Twig_Template->render(Array)
twig_render_template('core/themes/classy/templates/dataset/table.html.twig', Array)
Drupal\Core\Theme\ThemeManager->render('table', Array)
Drupal\Core\Render\Renderer->doRender(Array)
Drupal\Core\Render\Renderer->doRender(Array, )
Drupal\Core\Render\Renderer->render(Array, )
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}()
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1)
Drupal\ban\BanMiddleware->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1)
Stack\StackedHttpKernel->handle(Object, 1, 1)
Drupal\Core\DrupalKernel->handle(Object)