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 ('c7c90412e7cd5c18b0fe50f3ff9ccfed', -1, 1539760757, 1539760757, '36c6d41e', 9, 0, 0)

Line : 445
File : sessions.php