Fehler SUCHINDEX

{
    "error": true,
    "code": 0,
    "message": "Class \"FinderIndexer\" not found",
    "trace": "#0 
/usr/www/users/langena/Testumgebung/administrator/components/com_finder/src/Indexer/Adapter.php(261): PlgFinderSppagebuilder->index()\n#1 
/usr/www/users/xx/libraries/src/Plugin/CMSPlugin.php(289): Joomla\\Component\\Finder\\Administrator\\Indexer\\Adapter->onBuildIndex()\n#2 
/usr/www/users/xx/libraries/vendor/joomla/event/src/Dispatcher.php(454): Joomla\\CMS\\Plugin\\CMSPlugin->{closure:Joomla\\CMS\\Plugin\\CMSPlugin::registerLegacyListener():273}()\n#3 
/usr/www/users/xx/administrator/components/com_finder/src/Controller/IndexerController.php(189): Joomla\\Event\\Dispatcher->dispatch()\n#4 
/usr/www/users/xx/libraries/src/MVC/Controller/BaseController.php(730): Joomla\\Component\\Finder\\Administrator\\Controller\\IndexerController->batch()\n#5 
/usr/www/users/xx/libraries/src/Dispatcher/ComponentDispatcher.php(143): Joomla\\CMS\\MVC\\Controller\\BaseController->execute()\n#6 
/usr/www/users/xx/libraries/src/Component/ComponentHelper.php(361): Joomla\\CMS\\Dispatcher\\ComponentDispatcher->dispatch()\n#7 
/usr/www/users/xx/libraries/src/Application/AdministratorApplication.php(150): Joomla\\CMS\\Component\\ComponentHelper::renderComponent()\n#8 
/usr/www/users/xx/libraries/src/Application/AdministratorApplication.php(195): Joomla\\CMS\\Application\\AdministratorApplication->dispatch()\n#9 
/usr/www/users/xx/libraries/src/Application/CMSApplication.php(306): Joomla\\CMS\\Application\\AdministratorApplication->doExecute()\n#10 
/usr/www/users/xx/administrator/includes/app.php(58): Joomla\\CMS\\Application\\CMSApplication->execute()\n#11 
/usr/www/users/xx/administrator/index.php(32): require_once('
/usr/www/users/...')\n#12 {main}"
}