FTP without authorization is functional. But if you enable authorization, the FTP client answers that the password was not accepted. The password and username are correct. Below is a fragment of the system log:
Core::Syslog: the system log has been cleared.
Авг 27 19:18:01
pure-ftpd
(?@94.153.64.253) [INFO] New connection from 94.153.64.253
Авг 27 19:18:03
ndm
Core::Server: started Session /var/run/ndm.core.socket.
Авг 27 19:18:03
ndm
Core::Authenticator: user "IP_camera" authenticated, realm "Keenetic Giga", tag "ftp".
Авг 27 19:18:03
ndm
Core::Session: client disconnected.