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 ('3c44e5d7e945a91bce54432c13dd7927', -1, 1540115881, 1540115881, '36a16418', 0, 0, 0)

Line : 445
File : sessions.php