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 ('6c2b75df3cf2bbe66d258ecc05626182', -1, 1566045324, 1566045324, '22ef933b', 1, 0, 0)

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