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 ('6f751b95ff1cf1eb5b93915811828afc', -1, 1709623639, 1709623639, '2cc84d5c', -4, 0, 0)

Line : 187
File : sessions.php