Error message

• Warning: Attempt to read property "id" on null in mf_events_and_courses_entity_view() (line 184 of modules/mf_events_and_courses/mf_events_and_courses.module).

  mf_events_and_courses_entity_view(Array, Object, Object, 'teaser')
  call_user_func_array(Object, Array) (Line: 409)
  Drupal\Core\Extension\ModuleHandler->Drupal\Core\Extension\{closure}(Object, 'mf_events_and_courses') (Line: 388)
  Drupal\Core\Extension\ModuleHandler->invokeAllWith('entity_view', Object) (Line: 408)
  Drupal\Core\Extension\ModuleHandler->invokeAll('entity_view', Array) (Line: 288)
  Drupal\Core\Entity\EntityViewBuilder->buildMultiple(Array) (Line: 238)
  Drupal\Core\Entity\EntityViewBuilder->build(Array)
  call_user_func_array(Array, Array) (Line: 111)
  Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. See https://www.drupal.org/node/2966725', 'exception', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 859)
  Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 421)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array) (Line: 475)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 60)
  __TwigTemplate_3a2720e1864c6f601f8f8d0055a6f00f->doDisplay(Array, Array) (Line: 394)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 367)
  Twig\Template->display(Array) (Line: 379)
  Twig\Template->render(Array) (Line: 38)
  Twig\TemplateWrapper->render(Array) (Line: 39)
  twig_render_template('core/modules/views/templates/views-view-unformatted.html.twig', Array) (Line: 348)
  Drupal\Core\Theme\ThemeManager->render('views_view_unformatted', Array) (Line: 480)
  Drupal\Core\Render\Renderer->doRender(Array) (Line: 493)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array) (Line: 475)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 110)
  __TwigTemplate_6220d3eabb087cb25e833441844cfb93->doDisplay(Array, Array) (Line: 394)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 367)
  Twig\Template->display(Array) (Line: 379)
  Twig\Template->render(Array) (Line: 38)
  Twig\TemplateWrapper->render(Array) (Line: 39)
  twig_render_template('themes/bootstrap/templates/views/views-view.html.twig', Array) (Line: 348)
  Drupal\Core\Theme\ThemeManager->render('views_view', Array) (Line: 480)
  Drupal\Core\Render\Renderer->doRender(Array) (Line: 493)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array, ) (Line: 238)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 627)
  Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 231)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 128)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
  call_user_func(Array, Object, 'kernel.view', Object) (Line: 111)
  Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.view') (Line: 186)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
  Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 32)
  Drupal\big_pipe\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 191)
  Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 128)
  Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 82)
  Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle(Object, 1, 1) (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 704)
  Drupal\Core\DrupalKernel->handle(Object) (Line: 24)
  

• Warning: Undefined array key 0 in mf_events_and_courses_entity_view() (line 188 of modules/mf_events_and_courses/mf_events_and_courses.module).

  mf_events_and_courses_entity_view(Array, Object, Object, 'teaser')
  call_user_func_array(Object, Array) (Line: 409)
  Drupal\Core\Extension\ModuleHandler->Drupal\Core\Extension\{closure}(Object, 'mf_events_and_courses') (Line: 388)
  Drupal\Core\Extension\ModuleHandler->invokeAllWith('entity_view', Object) (Line: 408)
  Drupal\Core\Extension\ModuleHandler->invokeAll('entity_view', Array) (Line: 288)
  Drupal\Core\Entity\EntityViewBuilder->buildMultiple(Array) (Line: 238)
  Drupal\Core\Entity\EntityViewBuilder->build(Array)
  call_user_func_array(Array, Array) (Line: 111)
  Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. See https://www.drupal.org/node/2966725', 'exception', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 859)
  Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 421)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array) (Line: 475)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 60)
  __TwigTemplate_3a2720e1864c6f601f8f8d0055a6f00f->doDisplay(Array, Array) (Line: 394)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 367)
  Twig\Template->display(Array) (Line: 379)
  Twig\Template->render(Array) (Line: 38)
  Twig\TemplateWrapper->render(Array) (Line: 39)
  twig_render_template('core/modules/views/templates/views-view-unformatted.html.twig', Array) (Line: 348)
  Drupal\Core\Theme\ThemeManager->render('views_view_unformatted', Array) (Line: 480)
  Drupal\Core\Render\Renderer->doRender(Array) (Line: 493)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array) (Line: 475)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 110)
  __TwigTemplate_6220d3eabb087cb25e833441844cfb93->doDisplay(Array, Array) (Line: 394)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 367)
  Twig\Template->display(Array) (Line: 379)
  Twig\Template->render(Array) (Line: 38)
  Twig\TemplateWrapper->render(Array) (Line: 39)
  twig_render_template('themes/bootstrap/templates/views/views-view.html.twig', Array) (Line: 348)
  Drupal\Core\Theme\ThemeManager->render('views_view', Array) (Line: 480)
  Drupal\Core\Render\Renderer->doRender(Array) (Line: 493)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array, ) (Line: 238)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 627)
  Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 231)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 128)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
  call_user_func(Array, Object, 'kernel.view', Object) (Line: 111)
  Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.view') (Line: 186)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
  Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 32)
  Drupal\big_pipe\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 191)
  Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 128)
  Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 82)
  Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle(Object, 1, 1) (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 704)
  Drupal\Core\DrupalKernel->handle(Object) (Line: 24)
  

• Warning: Trying to access array offset on value of type null in mf_events_and_courses_entity_view() (line 188 of modules/mf_events_and_courses/mf_events_and_courses.module).

  mf_events_and_courses_entity_view(Array, Object, Object, 'teaser')
  call_user_func_array(Object, Array) (Line: 409)
  Drupal\Core\Extension\ModuleHandler->Drupal\Core\Extension\{closure}(Object, 'mf_events_and_courses') (Line: 388)
  Drupal\Core\Extension\ModuleHandler->invokeAllWith('entity_view', Object) (Line: 408)
  Drupal\Core\Extension\ModuleHandler->invokeAll('entity_view', Array) (Line: 288)
  Drupal\Core\Entity\EntityViewBuilder->buildMultiple(Array) (Line: 238)
  Drupal\Core\Entity\EntityViewBuilder->build(Array)
  call_user_func_array(Array, Array) (Line: 111)
  Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. See https://www.drupal.org/node/2966725', 'exception', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 859)
  Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 421)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array) (Line: 475)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 60)
  __TwigTemplate_3a2720e1864c6f601f8f8d0055a6f00f->doDisplay(Array, Array) (Line: 394)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 367)
  Twig\Template->display(Array) (Line: 379)
  Twig\Template->render(Array) (Line: 38)
  Twig\TemplateWrapper->render(Array) (Line: 39)
  twig_render_template('core/modules/views/templates/views-view-unformatted.html.twig', Array) (Line: 348)
  Drupal\Core\Theme\ThemeManager->render('views_view_unformatted', Array) (Line: 480)
  Drupal\Core\Render\Renderer->doRender(Array) (Line: 493)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array) (Line: 475)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 110)
  __TwigTemplate_6220d3eabb087cb25e833441844cfb93->doDisplay(Array, Array) (Line: 394)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 367)
  Twig\Template->display(Array) (Line: 379)
  Twig\Template->render(Array) (Line: 38)
  Twig\TemplateWrapper->render(Array) (Line: 39)
  twig_render_template('themes/bootstrap/templates/views/views-view.html.twig', Array) (Line: 348)
  Drupal\Core\Theme\ThemeManager->render('views_view', Array) (Line: 480)
  Drupal\Core\Render\Renderer->doRender(Array) (Line: 493)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 240)
  Drupal\Core\Render\Renderer->render(Array, ) (Line: 238)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 627)
  Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 231)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 128)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
  call_user_func(Array, Object, 'kernel.view', Object) (Line: 111)
  Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.view') (Line: 186)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
  Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 32)
  Drupal\big_pipe\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 191)
  Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 128)
  Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 82)
  Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle(Object, 1, 1) (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 704)
  Drupal\Core\DrupalKernel->handle(Object) (Line: 24)