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 ('a6c3e8c85a44380404c8859162a23000', -1, 1542409138, 1542409138, '36525d74', 7, 0, 0)

Line : 193
File : sessions.php