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 ('22e235935733b784c88f29ec6abc8184', -1, 1513306078, 1513306078, '365acf4b', 27, 0, 0)

Line : 189
File : sessions.php