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 ('992d2173419092f4102a961901a7f0e1', -1, 1529940243, 1529940243, '36e0ebb7', -2, 0, 0)

Line : 172
File : sessions.php