PHP Error when I try to open a richdocument

Hey guys,

I am running Nextcloud with richdocument app and collabora without problems for months, but now I am getting following PHP Error:

[index] Error: Pimple\Exception\UnknownIdentifierException: Identifier "OCA\Richdocuments\Middleware\WOPIMiddleware" is not defined. at <<closure>>

0. /var/www/html/nextcloud/lib/private/AppFramework/DependencyInjection/DIContainer.php line 297
   offsetGet("OCA\\Richdocume ... e")
1. /var/www/html/nextcloud/3rdparty/pimple/pimple/src/Pimple/Container.php line 118
   OC\AppFramework\DependencyInjection\{closure}("*** sensitive parameters replaced ***")
2. /var/www/html/nextcloud/lib/private/AppFramework/DependencyInjection/DIContainer.php line 166
   offsetGet("MiddlewareDispatcher")
3. /var/www/html/nextcloud/3rdparty/pimple/pimple/src/Pimple/Container.php line 118
   OC\AppFramework\DependencyInjection\{closure}("*** sensitive parameters replaced ***")
4. /var/www/html/nextcloud/lib/private/AppFramework/App.php line 110
   offsetGet("Dispatcher")
5. /var/www/html/nextcloud/lib/private/AppFramework/Routing/RouteActionHandler.php line 47
   main("OCA\\Richdocume ... r", "setSettings", "*** sensitive parameter replaced ***", {_route: "richdo ... "})
6. <<closure>>
   __invoke({_route: "richdo ... "})
7. /var/www/html/nextcloud/lib/private/Route/Router.php line 297
   call_user_func(OC\AppFramework\ ... {}, {_route: "richdo ... "})
8. /var/www/html/nextcloud/lib/base.php line 987
   match("/apps/richdocuments/ajax/admin.php")
9. /var/www/html/nextcloud/index.php line 42
   handleRequest()

Has anyone idea? I already tried to reinstall the richdocument app with remove and install with the console.php.