What might block the creation of thumbnails? My Drupal 8 does not create thumbnail. I have set my files folder's permission to 775 and the folder 2016-10 is not there.


  


There is no error shown in the log, and the temporary directory is /tmp.
Perhaps you need to look for this file: /var/www/httpd-logs/your_site.com.error.log

So, edit your sites/default/files/.htaccess

# Turn off all options we don't need.
#Options -Indexes -ExecCGI -Includes -MultiViews
Options -Indexes -ExecCGI -Includes