Hi there,
I hope anyone can help me.
I updated my Joomla site from J3.9.20 to the act. J3.9.23. and all runs well, but when editing an article I run into these issues. I activated site-tracing and get this output

In the backend:

Selecting an article via the articles-listview to edit.
Call to a member function getTable() on bool

.../libraries/src/MVC/Controller/FormController.php:362
Call stack

Function Location

1 () JROOT/libraries/src/MVC/Controller/FormController.php:362
2 Joomla\CMS\MVC\Controller\FormController->edit() JROOT/libraries/src/MVC/Controller/BaseController.php:710
3 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/administrator/components/com_content/content.php:21
4 require_once() JROOT/libraries/src/Component/ComponentHelper.php:402
5 Joomla\CMS\Component\ComponentHelper::executeComponent() JROOT/libraries/src/Component/ComponentHelper.php:377
6 Joomla\CMS\Component\ComponentHelper::renderComponent() JROOT/libraries/src/Application/AdministratorApplication.php:101
7 Joomla\CMS\Application\AdministratorApplication->dispatch() JROOT/libraries/src/Application/AdministratorApplication.php:159
8 Joomla\CMS\Application\AdministratorApplication->doExecute() JROOT/libraries/src/Application/CMSApplication.php:196
9 Joomla\CMS\Application\CMSApplication->execute()
JROOT/administrator/index.php:51

In the frontend
... I get this issue:

0 - Class 'ContentModelArticle' not found

Tracing in frontend does not work well, because of very much statements to run thru.

Can anyone help me to fix this?

Greetings HGH