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 ('b7ef4165b8f1bfa76e107710656b68f9', -1, 1713511616, 1713511616, '12743e2d', -9, 0, 0)

Line : 187
File : sessions.php