Upload file to an FTP server using WordPress Filesystem_API

Question

Trying to upload a text file from WordPress website to a remote FTP with standard WordPress Filesystem_API. The connection works fine, but could not upload files to the destination. The PHP standard ftp_put() works fine. File upload is successful using the FileZilla client. It's a plain FTP ( Not TLS, Not SSL )

Tried WordPress Developer guide - for ftpext, ftpsockets

function remote_ftp_upload_using_standard_wp($ftp_profile) {

    global $wp_filesystem;

    require_once ( ABSPATH . '/wp-admin/includes/file.php' );
    $connection_method = 'ftpext';
    $connection_options = array(
        'connection_type' => $connection_method,
        'hostname' => $ftp_profile['server'],
        'username' => $ftp_profile['user_name'],
        'password' => $ftp_profile['password'],
        'port' => $ftp_profile['port'],
    );
    WP_Filesystem($connection_options);

    if (!class_exists("WP_Filesystem_$connection_method")) {

        $abstraction_file = ABSPATH . 'wp-admin/includes/class-wp-filesystem-' . $connection_method . '.php';

        if (!file_exists($abstraction_file)) {
            return;
        }

        require_once $abstraction_file;
    }
    $method = "WP_Filesystem_$connection_method";

    $wp_filesystem = new $method($connection_options);
    $wp_filesystem->connect(); // RETURNS TRUE
    //var_dump($wp_filesystem->abspath());exit;
    //$wp_filesystem->touch('/test.txt');
    $wp_filesystem->put_contents('/test.txt', "hello"); // RETURNS FALSE
    //ftp_pasv( $wp_filesystem->link, false );
    return $wp_filesystem;
}