Class does not exist

I'll import a fresh copy of the database from a different tier and try your recommendation. Will get back to you soon. Thanks.

Hi Vernit,
Thank you for following up on this. I tried it on my local computer, re-installed the Activity Tracking 8.x-1.2+0-dev module (I installed the dev module to see if it would make a difference) and cleared the cache/rebuilt site. Previously, I was using Drupal 8.7.10. Now, I am testing on 8.8.0-rc1. It looks like the same result (though I'm seeing a somewhat different error message--it could be because of different module version, Drupal version, or different environment). No other issues with my Drupal install.

Here is a more detailed (and seemingly different) error message from the /activitytrackinglog page, if it helps:

The website encountered an unexpected error. Please try again later.

TypeError: Argument 5 passed to Drupal\activity_tracking\Services\ActivityTrackingService::__construct() must be an instance of Drupal\Core\Logger\LoggerChannelFactory, instance of Drupal\redirect_404\Render\Redirect404LogSuppressor given, called in /PATH/TO/SITE/docroot/core/lib/Drupal/Component/DependencyInjection/Container.php on line 285 in Drupal\activity_tracking\Services\ActivityTrackingService->__construct() (line 54 of modules/contrib/activitytracking/src/Services/ActivityTrackingService.php).

Drupal\activity_tracking\Services\ActivityTrackingService->__construct(Object, Object, Object, Object, Object) (Line: 285)
Drupal\Component\DependencyInjection\Container->createService(Array, 'activity_tracking.logger') (Line: 173)
Drupal\Component\DependencyInjection\Container->get('activity_tracking.logger') (Line: 68)
Drupal\activity_tracking\Form\ActivityTracking::create(Object) (Line: 28)
Drupal\Core\DependencyInjection\ClassResolver->getInstanceFromDefinition('\Drupal\activity_tracking\Form\ActivityTracking') (Line: 48)
Drupal\Core\Controller\HtmlFormController->getFormObject(Object, '\Drupal\activity_tracking\Form\ActivityTracking') (Line: 76)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151)
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: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 50)
Drupal\ban\BanMiddleware->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: 694)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

Thanks again for your time.

Regards,
Jason

Ok, I'll try but it may not be right away.