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 ('78f3d93cf29d43ca8878e304f4bc2420', -1, 1711709010, 1711709010, '12d1e53b', 0, 0, 0)

Line : 187
File : sessions.php