phpBB by Przemo : 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 ('1da88e37d6c5cad0e25ccc1b2d343bc6', -1, 1539732863, 1539732863, '36c60f14', 21, 0, 0)

Line : 445
File : sessions.php