FTP
551 Page Type Unknown
Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
Khi bạn thấy mã này
When attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
Cách khắc phục
Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.