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 ('2012d03a0e7df5bce58944125138f07b', -1, 1714041481, 1714041481, '0391ba06', -10, 0, 0)

Line : 187
File : sessions.php