phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_real_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('2d52eff9aa93cabd8888e48e8f0a1388', -1, 1438221517, 1438221517, '365af378', 2, 0)

Line : 158
File : /var/www/vhosts/pravniki.info/httpdocs/includes/sessions.php