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 ('8cbbe3722b2539e5f1a8a69e867a50e8', -1, 1561451300, 1561451300, '36a3d595', 14, 0, 0)

Line : 187
File : sessions.php