Internal Server Error when trying to install NC 11/12


I’m running an Owncloud 9.1.4 on Ubuntu Server 16.04 with PHP Version 7.0.22.

I would like to migrate to Nextcloud. So I

  1. downloaded and extracted to /var/www/nextcloud
  2. copied the data and configuration folders from /var/www/owncloud to /var/www/nextcloud
  3. downloaded the compatible app versions and extracted them to /var/www/nextcloud/apps
  4. dumped the owncloud mysql database and restored it into a new nextcloud database
  5. changed the database name / user / password in configuration.php
  6. changed the paths in configuration.php

But trying to request Nextcloud for upgrading in the browser I get “500 Internal Server Error”.

Even if i try to install NC 11/12 from scratch (just unzip the package to /var/www/nextcloud) I get the “500 Internal Server Error”.

OC 9.1.4 and other webapplications using php work fine with Apache 2.4 and PHP 7.0.22 on the same server.

What can I do to get Nextcloud 11/12 working?