Troubleshoot WordPress refusing an FTP connection

This article explains what to do if WordPress refuses an FTP connection despite having
the correct login information on Linux® operating systems. Perform the steps
in this article if you get the following error:

ERROR: There was an error connecting to the server, Please verify the settings are correct

1. Enable WP_DEBUG in the wp-config.php file. When you insert the following code in
   wp-config.php, the system logs all errors, notices, and warnings to
   wp-content/debug.log. It also hides the errors so that they do not interrupt page generation.

   a. Open wp-config.php in an editor.

   b. Insert a new line above the line: That's all, stop editing! Happy blogging.

   c. Insert the following lines where you added the new line and save the file:

   // Enable WP_DEBUG mode
   define( 'WP_DEBUG', true );
   
   // Enable Debug logging to the /wp-content/debug.log file
   define( 'WP_DEBUG_LOG', true );
   
   // Disable display of errors and warnings
   define( 'WP_DEBUG_DISPLAY', false );
   @ini_set( 'display_errors', 0 );
   
   // Use dev versions of core JS and CSS files (only needed if you are modifying these core files)
   define( 'SCRIPT_DEBUG', true );
   

2. If you have root access, check your PHP error log and the syslog in /var/log.

3. From a shell prompt, try connecting to localhost through FTP. Can you read and write to your plugins folder?
   From a remote machine, attempt the FTP connection to localhost and check your read and write permissions.

4. Add your FTP details in wp-config.php.

   a. Open wp-config.php in an editor.

   b. Insert a new line above the line: That's all, stop editing! Happy blogging.

   c. Insert the following lines where you added the new line and save the file:

   define( 'FS_METHOD', 'ftpext' );
   define( 'FTP_BASE', '/path/to/wordpress/' );
   define( 'FTP_CONTENT_DIR', '/path/to/wordpress/wp-content/' );
   define( 'FTP_PLUGIN_DIR ', '/path/to/wordpress/wp-content/plugins/' );
   define( 'FTP_PUBKEY', '/home/username/.ssh/id_rsa.pub' );
   define( 'FTP_PRIKEY', '/home/username/.ssh/id_rsa' );
   define( 'FTP_USER', 'username' );
   define( 'FTP_PASS', 'password' );
   define( 'FTP_HOST', 'ftp.example.org' );
   define( 'FTP_SSL', false );
   

Updater support plugin

If you continue to experience this error, install this plugin:
http://wordpress.org/plugins/ssh-sftp-updater-support/.

Installing the plugin adds the option for SFTP. After you install it, you can select SSH2 when prompted for
your FTP login information by choosing SSH2 at the bottom of the page. Leave the private key box empty.