phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('2014e320fe8ed3404ddb9ba82b85ee1b', -1, 1715259471, 1715259471, '0391ba06', -4, 0, 0)

Line : 189
File : sessions.php