when I uploaded the script to the server I got this error
Warning: Unknown: open(/tmp/sess_58f54ee6a828f04116c2ed97664497b2, 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 (/tmp) in Unknown on line 0
The error appeared when I call session_start(), although I set the permission of /tmp folder to 777.
Change session path where you can write data or contact server administrator about /tmp problem