Error 500 after downgrade


I made an Update from 13.06.1 to 14 RC2.
Then I get an Error 500.

Then I made es restore from the 13.06.1 files and the Database. But no luck.

This is the error log from Apache

[Sun Sep 09 18:45:09.741867 2018] [php7:warn] [pid 1574] [client] PHP Warning:  require(/var/www/cloud/3rdparty/composer/../symfony/polyfill-php70/bootstrap.php): failed to open stream: Permission denied in /var/www/cloud/3rdparty/composer/autoload_real.php on line 61
[Sun Sep 09 18:45:09.741884 2018] [php7:error] [pid 1574] [client] PHP Fatal error:  require(): Failed opening required '/var/www/cloud/3rdparty/composer/../symfony/polyfill-php70/bootstrap.php' (include_path='/var/www/cloud/3rdparty/pear/console_getopt:/var/www/cloud/3rdparty/pear/pear_exception:/var/www/cloud/3rdparty/pear/pear-core-minimal/src:/var/www/cloud/3rdparty/pear/archive_tar:/var/www/cloud/apps') in /var/www/cloud/3rdparty/composer/autoload_real.php on line 61

Nextcloud Log tells me 14 is installed :thinking: