powershell FTPS csv file

Question

I am trying to upload a csv file via FTPS as I need SSL enabled but this code keeps throwing an error message (particularly at line $rs = $ftp.GetRequestStream()):

$username = "username"
$password = "password"
$Url = "ftp://hosturl"
$filename = "somefile.csv"
$usessl=$true

try {
    $uri = New-Object System.Uri($url)
    $ftp = [System.Net.FtpWebRequest]::Create($uri)
    $ftp = [System.Net.FtpWebRequest]$ftp
    $ftp.Method = [System.Net.WebRequestMethods+Ftp]::UploadFile
    $ftp.Credentials = new-object System.Net.NetworkCredential($username, $password)
    $ftp.UseBinary = $true
    $ftp.UsePassive = $true
    $ftp.EnableSsl = $usessl
    $content = [System.IO.File]::ReadAllBytes($filename)
    $ftp.ContentLength = $content.Length
    $rs = $ftp.GetRequestStream()
    $rs.Write($content, 0, $content.Length)
    'File Uploaded.'
    $rs.Close()
    $rs.Dispose()
}
catch{
    Throw $_    
}

Error Message:

Exception calling "GetRequestStream" with "0" argument(s): "System error."