Error message

• Notice: Trying to access array offset on value of type null in Drupal\library\LibraryRest->getDict() (line 209 of modules/custom/library/src/LibraryRest.php).

  Drupal\library\LibraryRest->getDict('ACADEMICDEGREE', 'get', ) (Line: 105)
  Drupal\lib_users\Form\RegisterForm->buildForm(Array, Object)
  call_user_func_array(Array, Array) (Line: 531)
  Drupal\Core\Form\FormBuilder->retrieveForm('lib_users_register_form', Object) (Line: 278)
  Drupal\Core\Form\FormBuilder->buildForm('Drupal\lib_users\Form\RegisterForm', Object) (Line: 219)
  Drupal\Core\Form\FormBuilder->getForm('Drupal\lib_users\Form\RegisterForm') (Line: 65)
  lib_users_form_user_register_form_alter(Array, Object, 'user_register_form') (Line: 562)
  Drupal\Core\Extension\ModuleHandler->alter('form', Array, Object, 'user_register_form') (Line: 835)
  Drupal\Core\Form\FormBuilder->prepareForm('user_register_form', Array, Object) (Line: 279)
  Drupal\Core\Form\FormBuilder->buildForm(Object, Object) (Line: 219)
  Drupal\Core\Form\FormBuilder->getForm(Object) (Line: 20)
  nabrk_preprocess_page(Array, 'page', Array)
  call_user_func_array('nabrk_preprocess_page', Array) (Line: 287)
  Drupal\Core\Theme\ThemeManager->render('page', Array) (Line: 422)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 201)
  Drupal\Core\Render\Renderer->render(Array) (Line: 479)
  Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 100)
  __TwigTemplate_8d001f9b2cad9280318639ae34de7dbbe28a7c0afb482d5cfad50f11f19ef878->doDisplay(Array, Array) (Line: 405)
  Twig\Template->displayWithErrorHandling(Array, Array) (Line: 378)
  Twig\Template->display(Array) (Line: 390)
  Twig\Template->render(Array) (Line: 55)
  twig_render_template('themes/custom/nabrk/templates/layout/html.html.twig', Array) (Line: 384)
  Drupal\Core\Theme\ThemeManager->render('html', Array) (Line: 422)
  Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 201)
  Drupal\Core\Render\Renderer->render(Array) (Line: 162)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 564)
  Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 163)
  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: 142)
  Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.view') (Line: 174)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
  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: 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: 23)
  Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 709)
  Drupal\Core\DrupalKernel->handle(Object) (Line: 19)