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 ('8994e5b9fc21d5c68af3abffe668e732', -1, 1561069636, 1561069636, '3698269a', 60, 0, 0)

Line : 187
File : sessions.php