Kindly check your generation and pub folder have full root permission set.
find var vendor pub/static pub/media app/etc -type f -exec chmod u+w {} \;
find var vendor pub/static pub/media app/etc -type d -exec chmod u+w {} \;
chmod u+x bin/magento
check below links for permission,
https://devdocs.magento.com/guides/v2.0/install-gde/prereq/file-system-perms.html
If permission is set, please check system.log of your site.