Download from FTP

Hello guys, I have a FTP that contains a bunch of files and it's protected by user and password.

I'm trying to pull an image from it and assign it to a geometry.

this is the code I'm using

 public static IEnumerator urlTexture(){
     string url = "ftp://username:password@HOST_IP/images/00013/01_01.jpg";
     Debug.Log ("Request sent");
     GlobalVariables.myUrl [1] = new WWW (url_left);
     yield return GlobalVariables.myUrl [1];
     }

This code works just fine whenever I pull an image from a http address without having to provide credentials. The credentials are correct but it's just not working.

If I get the Url[1].url and paste the string it returns in my browser (both firefox and chrome), it works perfectly.

any clue about why it's not working from Unity?

Thank you very much