SFTP stands for Secure File Transfer Protocol. It was designed as an extension of the SSH (Secure Shell) protocol. This is because it runs over a secure channel. SFTP is not to be confused with File Transfer Protocol (FTP) which is similar but not secure. In this article, we shall be discussing the simple steps to fix the following error “Authentication Failed: How to fix critical error could not connect to WordPress SFTP Server”. Kindly refer to these related articles: There has been a critical error on this website please check your site admin email inbox for instructions, and how to Fix WordPress Error “The Link You Followed Has Expired”.

Note: Each SFTP client is slightly different. In my case, I am using FileZilla to connect. Here is an exciting article on running FileZilla Client on Mac: How to Transfer Files to WordPress via SFTP.

Why was the error “Authentication Failed: How to fix critical error could not connect to Server” prompted?

This error was prompted due to wrong password usage. As you can see in the status message, “Access was denied”. Kindly also take a look at the image below for more information.

Fix critical error could not connect to Server

In order to connect to WordPress SFTP Server, you would need to access WordPress Host Configuration and navigate to the SFTP/SSH credentials section. Copy the relevant credentials to the FileZilla client to connect. The image below shows the relevant credentials necessary for establishing an SFTP connection.

In order to reveal the password, kindly click on “Reset Password”. When this is done, the password will be displayed. Here is an article on how to import a user profile in Windows to another PC.

As you can see below, the connection to the WordPress SFTP server has been established successfully.

Please also see how to Fix critical Veeam Backup and Replication 9.5, 10, and 11 vulnerabilities, how to transfer data from an old PC to a new PC and “WordPress site on Azure: How to create a website hosted in Azure“.

Grant FileZilla Folder Access

If this is your first time connecting, you would be prompted to allow access to your download, documents, desktop, and Dropbox if connected etc.

If the files will wish to transfer to the remote locations available in any of these folders, kindly click on OK to enable access.

I hope you found this blog post helpful on “Authentication Failed: How to fix critical error could not connect to WordPress SFTP Server”. Please let me know in the comment section if you have any questions.