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 ('a6d31e3e51b8ca9a1b6d9bb85dc56a9e', -1, 1711614864, 1711614864, '2cc06bff', 4, 0, 0)

Line : 187
File : sessions.php