Error when installing

Warning: session_start(): open(/tmp/sess_4b6666f3644596b1783093bab13e1ab2, O_RDWR) failed: Permission denied (13) in /home/sandbox/public_html/sandbox/wp-content/plugins/wp-file-upload/wordpress_file_upload.php on line 2

Warning: session_start(): Cannot send session cache limiter – headers already sent (output started at /home/sandbox/public_html/sandbox/wp-content/plugins/wp-file-upload/wordpress_file_upload.php:2) in /home/sandbox/public_html/sandbox/wp-content/plugins/wp-file-upload/wordpress_file_upload.php on line 2

Warning: Cannot modify header information – headers already sent by (output started at /home/sandbox/public_html/sandbox/wp-content/plugins/wp-file-upload/wordpress_file_upload.php:2) in /home/sandbox/public_html/sandbox/wp-includes/pluggable.php on line 1196

Warning: Unknown: open(/tmp/sess_4b6666f3644596b1783093bab13e1ab2, 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

https://wordpress.org/plugins/frontend-uploader/