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 ('a6baf9d1bcd02d1d638fea52aa5e6bb4', -1, 1635321521, 1635321521, '23af6b4d', -4, 0, 0)

Line : 187
File : sessions.php