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 ('635e01c09e4914e4694fee79eb90d1df', -1, 1711717715, 1711717715, '2cc0f790', -4, 0, 0)

Line : 187
File : sessions.php