FTP client login problems

[peman]

[15:44:19] SmartFTP v3.0.1021.3
[15:44:19] Resolving host name "xxxxxx"
[15:44:19] Connecting to xxxxxxxx Port: 21
[15:44:19] Connected to xxxxxx.
[15:44:20] 220 zFTPServer v3.3, build 2008-06-18 12:11 ready.
[15:44:20] USER xxxx@xxxx.net
[15:44:20] 331 User name received, need password.
[15:44:20] PASS (hidden)
[15:44:20] 530 Login not accepted
[15:44:20] Server closed connection
[15:44:20] Connect failed. Waiting to retry (30s)...

I recieve this everytime i try to login with an external ftp client like SmartFTP. The FTP filemanager works fine but sometimes hangs but it works and our customer can login.

but what is up with the ftp client, am i not supposed to logiin with ordinary ftp client?

/Martin