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 ('2c8de81ed6cf06bc1458c3cfd5f951c3', -1, 1539729247, 1539729247, '36c60f14', -8, 0, 0)

Line : 445
File : sessions.php