phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO pcxhpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a0f6794464071225fa9c390c78eeb74a', -1, 1568907809, 1568907809, '12cd6d52', 2, 0, 0)

Line : 186
File : sessions.php