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 ('0504af2f0ca4b7e6c9f32b1b1be4c236', -1, 1560910255, 1560910255, '36a11ff7', -9, 0, 0)

Line : 187
File : sessions.php