phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO darkdoor_phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin, is_robot) VALUES ('e75988581a4a9e45d6e474966019b3f6', -1, 1568671569, 1568671569, '23ad2f2b', 3, 0, '0', '0')

Line : 175
File : sessions.php