phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO iabb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a2c57b3ef4d4834409df3aefb8d4cae8', -1, 1561069470, 1561069470, '3698269a', 60, 0, 0)

Line : 187
File : sessions.php