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 ('1b2db5532dc87a4b65b0d3ca0e66e969', -1, 1566089141, 1566089141, '22ef9e6b', -9, 0, 0)

Line : 172
File : /home/rebkell/public_html/boards/includes/sessions.php