
The other day I had to connect to my web server. I use FileZilla for connecting to FTP servers. FileZilla is a free and open source GUI software that allows you to connect to an FTP server in Linux.
When I entered the hostname and password and tried to connect to the FTP server, it gave me the following error:
Error: Cannot establish FTP connection to an SFTP server. Please select proper protocol.
Error: Critical error: Could not connect to server
The error looks like this in the FileZilla interface.

Let me tell you why you see this error and what you can do to 'fix' it.
Fixing ‘Critical error: Could not connect to server’ in Linux
By reading the error message itself made me realize my mistake. I was trying to establish an FTP connection with an SFTP server.
You see, I had SFTP setup on the Linux server. Clearly, I was not using the correct protocol which should have been SFTP and not FTP.
As you can see in the picture above, FileZilla defaults to the FTP protocol.
Solution for “Cannot establish FTP connection to an SFTP server”
The solution is simple. Use SFTP protocol instead of FTP.
The one problem you might face is knowing how to change the protocol to SFTP. This is where I am going to help you.
In the FileZilla menu, go to File->Site Manager.

In the Site Manager, go in General tab and select SFTP in Protocol. Also fill in the host server, port number, user password etc.

I hope you can handle things from here onward.
FileZilla is an excellent GUI tool for SFTP browsing. This tutorial will help you learn the basics of FileZilla.

I hope this quick tutorial helped you to fix “Cannot establish FTP connection to an SFTP server. Please select proper protocol.” problem.
If you have questions or suggestions, do let me know. If this article helped you fix the problem, I won’t mind a simple ‘thanks’ comment :)
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