This article explains 400 series response code.
The command was not accepted and the requested action did not take place, but the error condition is temporary and the action may be requested again.
401 FTP Response code
The following error appears when trying to access File Sharing.
401 Unauthorized, you are not logged in
All Serv-U MFT versions
The link generated during file sharing is inaccessible because it is not resolving to the right domain url. There is an unsupported character on the domain URL on File Sharing setting of the Serv-U MC.
Delete the special character and make sure to put the File Sharing domain URL only.
421 FTP Response code
A 421 response code indicates that while the service is still running, the service is unavailable at the time of connection. It indicates that the server will be restarting as soon as it finishes processing pending operations (usually any file
transfers currently in progress). It is considered a transient negative response, which means the client is encouraged to issue the same command again at a later time when it can be accepted.
421 Service not available, closing control connection.
A 421 response code may be given in response to any FTP command or connection attempt if the FTP server knows it must shut down.
425 FTP Response code
A 425 response code may be sent in response to any command requiring the usage of a data connection if the server is unable to open a data connection. This is considered a transient negative reply as it is considered to be a temporary condition.
It may indicate that the server does not immediately have the resources available to open a data connection. In this case, the client is encouraged to restart the FTP transaction and try again.
425 Can't open data connection.
426 FTP Response code
A 426 response code may be sent in response to any command requiring the usage of a data connection. It is considered a transient negative reply as it is considered to be a temporary condition. It is usually sent when the data connection is
unexpectedly closed before the completion of a data transfer. In this case, the client is encouraged to restart the FTP transaction and try again.
426 Connection closed; transfer aborted.
- 110, 120, 125, 150 FTP response codes
- 202, 211, 212, 213 FTP response codes
- 214, 215, 220, 221 FTP response codes
- 225, 226, 227, 230 FTP response codes
- 232, 234, 250, 253, 257 FTP response codes
- 331, 332, 334, 336, 350 FTP response codes
- 431, 450, 451, 452 FTP response codes
- 500, 501, 502, 503, 504 FTP response codes
- 536, 550, 551, 552, 553 FTP response codes