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 ('8dbc8d7b2cbd3f8f683a9a18673942ac', -1, 1569047931, 1569047931, '23afbf96', -9, 0, 0)

Line : 187
File : sessions.php