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 ('09ab2d97ca06a1b7eb72a4d62160f166', -1, 1711700798, 1711700798, '2cc8ed70', -4, 0, 0)

Line : 187
File : sessions.php