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 ('d61c3f5d60b47c47c6a56166e058e501', -1, 1566593980, 1566593980, '22ecbed8', -10, 0, 0)

Line : 187
File : sessions.php