phpBB : 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 ('1c6a4c32b7dc182f06963aaa8b45dd80', -1, 1566115267, 1566115267, '12e835e7', 2, 0, 0)

Line : 187
File : sessions.php