The FileZilla is an FTP client also known as FTP or FTPs or SFTP client used to manage files i.e. both upload and download to and from the live server. The server must be connected before the upload can be made but some times connection encountered some errors. The errors may differ but the resolution here is based on 421 Too many connections. The connection error appears as given below:

Response: 421 Too many connections (8) from this IP
Error: Could not connect to server

The number indicated as (8) may vary as different servers have different FTP settings by the respective hosting service provider. The error simply means that the FTP receives multiple connection from your IP more than the permitted number of connection as set in the FTP server settings.

It is very interesting that the error is resolved in a simple process by reducing the multiple number of connections in the FileZilla.

A- The Actual Meaning of “421 Too Many Connections”

As the error code 421 implies that FTP cannot connect to the server as it receives too many connection concurrently at a time e.g.

The following aspect indicates the error:

It implies that the FTP server was configured to accept at most 8 simultaneous number of FTP connection from an IP address and after that, another connection was established. As part of managing server resources, some shared hosting company set up connection limit of the FTP settings on their servers.

B- Situation Leading to the Error

Causes of the error are many and below are some of them but resolving them is the key point to note.

B- (i) FileZilla can open too may connections at a time:

A typical example is given below:

In this tutorial, the FTP client was configured to accept maximum connection of 8 and as the nine connection was sent, it was rejected thereby leading to the 421 error.

B- (ii) Previous FTP connections remained active

Some times connections found to be idle on the server after previously connected and disconnected. It is actually, disconnected on the FileZilla client but the server is counting the connection as active since the previous session is still active until the FTP server clear it.

B- (iii) FileZilla is opened in many windows

When many instances or multiple FileZilla client is opened and each is running, the instance must establish connection e.g. as given below:

If another connection can be established, then error will as below:

B- (iv) Sharing the same Internet connection IP by multiple systems

For instance, if computers A, B and C are sharing the same IP on the network and the connection limit is based on IP.

As the three computers are connected to the FTP server via same IP, the connection is counted on the IP.

B- (v) Restriction of connection by the Hosting service provider

The FTP connection is usually, manage and controlled by the Hosting service provider on the shared server. The service provider set the limited number that the FTP can be connected at once .e.g. as given below:

In this case, the connection is set to allow 8 FTP connection at a time.

C- Resolving the Error

FileZilla can be configured to use very minimal simultaneous connections. It can start with 1 or 2 as indicated below:

or:

When the hosting service provider enables multiple connection, then the figure can easily be increased on the FTP client. Some shared hosting company are using minimal number to reduce connection problem or abuse.

D- Step-by-Step: To Increase/Decrease Connections Limit in FileZilla

Step 1: Open FileZilla

Open the FileZilla application on the computer and click on “File”.

Step 2: Click on “Site Manager”.

On the FileZilla client menu, select:

File >> Site Manager

Step 3: Select Your FTP Website

While on the Site Manager, select the website/server that is displaying the error. e.g. as given below:

Step 4: Open Transfer Settings

Click “Transfer Settings”.

This is where the connection limit settings is located on the FileZilla.

Step 5: Enable the Connection Limit

Tick on “Limit number of simultaneous connections”

Then enter:

in:

Maximum number of connections

Here is the setting method