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 ('62e0ecf7693581817a5d7c12b2cf5bcd', -1, 1555612354, 1555612354, '3437bae1', 2, 0, 0)

Line : 187
File : sessions.php