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 ('df7460d8e3b6f32107ea570f273b79ad', -1, 1728959516, 1728959516, '23ad3012', -8, 0, 0)

Line : 172
File : sessions.php