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 ('800e11137c64401a6378f430a120bcc3', -1, 1768304850, 1768304850, 'd849d81a', -10, 0, 0)

Line : 187
File : sessions.php