List of Common FileZilla Pro CLI Errors

Connection timeout

There are a few different reasons that a connection timeout can occur:

Slow or unreliable connection

Somewhere between your Local machine and the host server is a slow or unreliable connection.

To counter this increase the value of the engine.timeout setting. The default value is 20

    fzcli> set engine.timeout 30

Incorrectly configured server

If the connection times out on large file transfers, a server somewhere between your local
computer and the Remote server might be incorrectly configured, identifying the command
channel of the connection as ‘idle’, and closing it. This is a misconfiguration, and ideally
should be handled by opening a support ticket with the owner of the server.

You might be able to counter it temporarily by enabling the keep-alive commands with the
engine.ftp.send_keepalive setting:

    fzcli> set engine.ftp.send_keepalive 1

Critical error: Could not connect to server

This error usually means that the login details or method set for a Remote connection are


  • The user ID and password that you entered. Note that for many website hosting providers,the
    user ID and password that you use to login to the website itself will be different to the user ID
    and password that you need for file transfer connections.
    Look for FTP or SFTP or SSH connection details in information provided by the hosting provider.

Status: Connection attempt failed with “ECONNREFUSED – Connection refused by
server” message

If the connection is failing with the status message above, there might be a Local network
configuration issue.

Another possible cause is that the connection is being blocked by a firewall. If you have a
local firewall or an antivirus, try to disable it. If that works you may need to add an exception
to the firewall configuration to grant FileZilla Pro CLI permanent access to the

If you are in a corporate network, you may need to ask the network administrator to open
specific FTP ports. Most FTP servers use port 21, SFTP servers use port 22 and FTPS (implicit mode)
use port 990 by default.

Login failure

There are a couple of reasons that your login might fail for a particular server:

Incorrect credentials

Check that you’re using the FTP login details provided by your server administrator or hosting
provider. These will generally be different to the login details you use to gain access to
website functionality or your website hosting account.

Firewall or antivirus is blocking FileZilla Pro CLI

Some firewall and antivirus programs block file transfer connections by injecting false login
failures. Check the settings on any firewall or antivirus scanning programs, or check with
your network administrator to see if this might be happening to you.

Issue on the server end

If you’ve checked all of these possibilities and you’re still having trouble logging in, contact
your server administrator or hosting provider.

Files aren’t transferred or deleted

A failure to transfer or delete a file on a remote server is generally caused by permissions or
a lock set on the file.

File permissions don’t allow the current operation

Copy the displayed error message and contact your server administrator or server hosting
provider for assistance. Include the text of the error message, as it may assist the person
handling the help request.

The directory is protected

Check the directory that you’re trying to transfer files to. Is it protected, or a system directory?
Try transferring a file to a different directory.

The file is open in another program

Windows machines tend to lock files that are currently being used by an application. While
the file is locked, FileZilla Pro CLI won’t be able to transfer it. Try again when the
file is not open in another application.

Directory listings and file transfers fail

If you can connect to a remote server in FileZilla Pro CLI using FTP or FTP with
TLS, but not see remote directory listings or transfer files, there is probably something between
FileZilla Pro CLI and the remote server that is interfering with the connection.
Generally this will be a virus scanner, firewall, or NAT router.

Use FTP Test at to find out where in the connection the problem lies.
If the test connection fails, the problem is on the Remote end – talk to your system administrator or hosting provider for assistance.

If the test connection succeeds, then the problem is probably on your Local computer or network.
Some steps that you can take to diagnose the problem are:

  • Check your local computer’s antivirus software. Its settings, list of blocked applications,
    or logs might show that it has blocked FTP commands from FileZilla Pro CLI.
  • Check your local computer’s firewall, if one is enabled. Most modern Windows machines
    have a native firewall enabled by default; open Windows Defender Security
    Center (Windows 10) and click on Firewall & network protection to check firewall
    settings or to configure the firewall to let FileZilla Pro CLI access remote
  • Are you using active-mode FTP? (see Active vs Passive Mode) If so, you may need to configure
    the NAT router to allow it. See FTP Active Mode Configuration for instructions,
    or go to for a more in-depth
    discussion of network configuration.
  • Is your internet service provider blocking FTP transfers using an ISP-level firewall or
    NAT router? If so, your only option might be to switch to a different ISP.

Uploads fail but downloads work

If you can download files from a remote server but not upload to, the most common reason
is that the server has run out of disk space, or you’ve exceeded a storage quota assigned to
the FTP user or group (for example, your company). If you think this might be the problem,
try deleting some files from the remote server and try again to upload files.

Depending on the server, you might be able to check the disk space currently available to
you in a user dashboard. If not, check with your web hosting service or server administrator.

Very occasionally, a server’s file system might experience technical difficulties to the point
that all files are read-only – you can look at them and download them, but no changes can be
made to existing files or new files added. Contact your server administrator or web hosting
provider for assistance.

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