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 ('4b2efbe65bf549c682483c012d1515fa', -1, 1714000146, 1714000146, '0391821f', -4, 0, 0)

Line : 187
File : sessions.php