phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('ada99b7c652deeca5f7c949f5d07fd0c', -1, 1440928284, 1440928284, '36e282c2', 0, 0)

Line : 158
File : sessions.php