How to fix this SSH access connection failure?

Question

I'm trying to connect to a server as usual, but now I'm getting errors to connect:

This is using putty from Windows OS.

Using username "admin".
You are trying to access a restricted zone. Only Authorized Users allowed.
Access denied
Using keyboard-interactive authentication.
Password:

This is trying to connect from terminl in a linux OS:

[root@abc ~]# ssh [email protected]
You are trying to access a restricted zone. Only Authorized Users allowed.
Password:
Password:
Connection closed by 111.222.333.444

This is from linux terminal using FTP:

[root@abc~]# ftp -n 111.222.333.444
Connected to 111.222.333.444 (111.222.333.444).
220 ftp server ready.
Remote system type is System.
ftp> user
(username) admin
430 Require auth before enter.
Login failed.
ftp>

But if I use Filezilla in Windows OS with the simple configuration in the image below, the FTP connection works (with SFTP doesn't work with Filezilla).

What could be the problem? how to fix it? Thanks in advance.

Answer 1

Your FTP error message says the 'auth' command is required, which in FTP actually means activating TLS using 'auth tls', like Filezilla does when you select "Explicit FTP over TLS".

The system built-in FTP clients usually don't support that. I would recommend lftp as a replacement.

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Your SSH error message says you're not allowed to use SSH with this server.

SFTP is actually transported over SSH (it's not a FTP variant), so it will always give the same results as SSH clients.