Trying to create new pager, module crashes

When trying to create my first pager, I click 'add new pager' button and:

Warning: Invalid argument supplied for foreach() in /app/core/lib/Drupal/Component/Utility/NestedArray.php on line 327
The website encountered an unexpected error. Please try again later.
TypeError: Argument 2 passed to Drupal\pagerer\Plugin\PagererStyleManager::createInstance() must be of the type array, null given, called in /app/modules/contrib/pagerer/pagerer.module on line 176 in Drupal\pagerer\Plugin\PagererStyleManager->createInstance() (line 36 of modules/contrib/pagerer/src/Plugin/PagererStyleManager.php).
Drupal\pagerer\Plugin\PagererStyleManager->createInstance(NULL, NULL) (Line: 176)
template_preprocess_pagerer_base(Array, 'pagerer_base', Array) (Line: 287)
Drupal\Core\Theme\ThemeManager->render('pagerer_base', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 52)
__TwigTemplate_12c1ad5e63590757eb24a820843c77f821de97ec51f56dc692c0367e4fe0386b->doDisplay(Array, Array) (Line: 428)
Twig_Template->displayWithErrorHandling(Array, Array) (Line: 399)
Twig_Template->display(Array) (Line: 407)
Twig_Template->render(Array) (Line: 64)
twig_render_template('modules/contrib/pagerer/templates/pagerer.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('pagerer', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 450)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 450)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 582)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
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('kernel.view', Object) (Line: 156)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 99)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 693)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

On Drupal 8.6.7
Module Version: 8.x-1.4