Can not open App Store at NC 18


unfortunately I can not open the App Store at the web page.
I got the following Error in the Logs.

[index] Error: Exception: Argument 2 passed to OC\App\DependencyAnalyzer::analyze() must be of the type bool, null given, called in /var/www/html/nextcloud/apps/settings/lib/Controller/AppSettingsController.php on line 277 at <<closure>>

0. /var/www/html/nextcloud/lib/private/AppFramework/App.php line 125
   OC\AppFramework\Http\Dispatcher->dispatch(OCA\Settings\Con ... {}, "listApps")
1. /var/www/html/nextcloud/lib/private/AppFramework/Routing/RouteActionHandler.php line 47
   OC\AppFramework\App::main("OCA\\Settings\\ ... r", "listApps", OC\AppFramework\ ... {}, {_route: "settings.AppSettings.listApps"})
2. <<closure>>
   OC\AppFramework\Routing\RouteActionHandler->__invoke({_route: "settings.AppSettings.listApps"})
3. /var/www/html/nextcloud/lib/private/Route/Router.php line 299
   call_user_func(OC\AppFramework\ ... {}, {_route: "settings.AppSettings.listApps"})
4. /var/www/html/nextcloud/lib/base.php line 1008
5. /var/www/html/nextcloud/index.php line 38

GET /index.php/settings/apps/list

I tried my backup with nc 17 but same behavior. Unfortunately I did not try it for a long time.

System is
Raspbian Buster on a Raspber PI 4 Model B
Web Server is Apache.

Did anyone else see this error before?