[Gelöst]Migrationsassistent lässt sich nicht installieren

Da ist nur eine prod.log drin mit folgendem Inhalte:

[2019-10-10 11:27:45] request.INFO: Matched route "frontend.cms.page". {"route":"frontend.cms.page","route_parameters":{"_route":"frontend.cms.page","id":null,"XmlHttpRequest":true,"_controller":"Shopware\\Storefront\\Controller\\CmsController::page"},"request_uri":"https://domain.url/widgets/cms","method":"GET"} []
[2019-10-10 11:27:45] app.DEBUG: #1 Rule detection: Customers from USA with priority 100 [] []
[2019-10-10 11:27:45] app.DEBUG: #2 Rule detection: Cart >= 0 with priority 100 [] []
[2019-10-10 11:27:45] app.DEBUG: #3 Rule detection: Cart >= 0 (Payment) with priority 100 [] []
[2019-10-10 11:27:45] app.DEBUG: #4 Rule detection: Sunday sales with priority 2 [] []
[2019-10-10 11:27:45] app.DEBUG: #5 Rule detection: All customers with priority 1 [] []
[2019-10-10 11:27:45] php.CRITICAL: Argument 1 passed to Shopware\Storefront\Controller\CmsController::page() must be of the type string, null given, called in /var/www/clients/client1/web1/web/sw6/vendor/symfony/http-kernel/HttpKernel.php on line 151 {"exception":"[object] (Symfony\\Component\\Debug\\Exception\\FatalThrowableError(code: 0): Argument 1 passed to Shopware\\Storefront\\Controller\\CmsController::page() must be of the type string, null given, called in /var/www/clients/client1/web1/web/sw6/vendor/symfony/http-kernel/HttpKernel.php on line 151 at /var/www/clients/client1/web1/web/sw6/vendor/shopware/storefront/Controller/CmsController.php:48)"} []
[2019-10-10 11:27:45] request.CRITICAL: Uncaught PHP Exception TypeError: "Argument 1 passed to Shopware\Storefront\Controller\CmsController::page() must be of the type string, null given, called in /var/www/clients/client1/web1/web/sw6/vendor/symfony/http-kernel/HttpKernel.php on line 151" at /var/www/clients/client1/web1/web/sw6/vendor/shopware/storefront/Controller/CmsController.php line 48 {"exception":"[object] (Symfony\\Component\\Debug\\Exception\\FatalThrowableError(code: 0): Argument 1 passed to Shopware\\Storefront\\Controller\\CmsController::page() must be of the type string, null given, called in /var/www/clients/client1/web1/web/sw6/vendor/symfony/http-kernel/HttpKernel.php on line 151 at /var/www/clients/client1/web1/web/sw6/vendor/shopware/storefront/Controller/CmsController.php:48)"} []