phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a9019449cff7e9783a64a2ce26d150d2', -1, 1419136912, 1419136912, '3657b4b5', -1, 0, 0)

Line : 187
File : sessions.php