Error after install theme with plugin unyson

Error after install theme with plugin unyson

I am having a problem in unyson plugin when installed following errors appear below

Warning: session_start() [function.session-start]: open(/var/lib/php-cgi/session/sess_s39fifp6ivoa0rgj7tofuelgv0, O_RDWR) failed: No such file or directory (2) in /home/storage/5/f6/7b/proadsp/public_html/wp-content/plugins/unyson/framework/helpers/class-fw-flash-messages.php on line 230
(one in the top of the page)

Warning: Unknown: open(/var/lib/php-cgi/session/sess_s39fifp6ivoa0rgj7tofuelgv0, O_RDWR) failed: No such file or directory (2) 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-cgi/session) in Unknown on line 0
(and those at the bottom)

I’ve tried reinstalling and not worked. Without this plugin page is without this error, but this issue need to use this plugin.

https://ww.wp.xz.cn/plugins/unyson/