Internal Server Error docker nextcloud setup

I hope someone can help me:-) i have installed nextcloud over portainer (docker). The nextcloud Container is running But i cannot access the webui. I got the error:

Internal Server Error

The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the webserver log.

nextcloud log Dateien which i get over the portainer webui is:

thrown in /config/www/nextcloud/cron.php on line 162

PHP Warning: include(/config/www/nextcloud/lib/composer/composer/…/…/…/lib/private/Cache/CappedMemoryCache.php): failed to open stream: No such file or directory in /config/www/nextcloud/lib/composer/composer/ClassLoader.php on line 444

PHP Warning: include(): Failed opening ‘/config/www/nextcloud/lib/composer/composer/…/…/…/lib/private/Cache/CappedMemoryCache.php’ for inclusion (include_path=’.:/usr/share/php7’) in /config/www/nextcloud/lib/composer/composer/ClassLoader.php on line 444

PHP Fatal error: Uncaught Error: Call to a member function getLogger() on null in /config/www/nextcloud

Pls help me to solve this issue