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 ('465ab4fb822aeaf5ff6f5b0777362d95', -1, 1438370542, 1438370542, '36904fc8', 32, 0)

Line : 158
File : sessions.php