I was getting the following error on a *fresh* CentOS…
Warning: Unknown: open(/var/lib/php/session/sess_isu2r2bqudeosqvpoo8a67oj02, O_RDWR) failed: Permission denied (13) in Unknown on line 0
Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/lib/php/session) in Unknown on line 0
This will do the work…
chown -R nginx:nobody /var/lib/php/session && chmod -R 770 /var/lib/php/session