phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a66be969947c9301060b2cd500ce6188', -1, 1422698623, 1422698623, '36cd2615', -4, 0, 0)

Line : 187
File : sessions.php