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 ('bf31c23d83d08754cbf74f035ee13bb6', -1, 1492991289, 1492991289, '3651d0ad', -1, 0, 0)

Line : 172
File : sessions.php