Having difficulty logging in to the mod site on Google Chrome.

I keep receiving the following text on every page on xenoversemods.com/ - this is also being presented as an error message when I attempt to log in.
"Warning: session_start(): open(/var/cpanel/php/sessions/ea-php56/sess_t5nrejic7i0vc3a6uh8o9ts2n6, O_RDWR) failed: No space left on device (28) in /home/zenin/public_html/xenoversemods.com/wp-content/plugins/wordpress-social-login/wp-social-login.php on line 64



Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home/zenin/public_html/xenoversemods.com/wp-content/plugins/wordpress-social-login/wp-social-login.php:64) in /home/zenin/public_html/xenoversemods.com/wp-content/plugins/wordpress-social-login/wp-social-login.php on line 64"

The only advice given is to enable cookies - sadly they're already enabled. Anyone have any advice?