phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO forum_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('da1a4f4162287e133a27fba07d0e172f', -1, 1464710109, 1464710109, '3650b2ac', -1, 0)

Line : 158
File : sessions.php