I've posted another question to resolve this issue: http://drupal.stackexchange.com/questions/197400/500-server-errorhttps://drupal.stackexchange.com/questions/197400/500-server-error [1]: https://www.drupal.org/documentation/install
replaced http://drupal.stackexchange.com/ with https://drupal.stackexchange.com/
added a tag to identify that the question is related to drupal8