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, session_admin) VALUES ('15b9704a8b46c1821c14389273a3bef6', -1, 1498132374, 1498132374, '369221f1', 2, 0, 0)

Line : 172
File : sessions.php