Hi there, Milotheminer! The Hopper Duo is not compatible with the Sling adapter, and Chadt4141 is correct that they are no longer supported. I would be happy to take a look at your account for upgrade options to a Hopper with Sling or Hopper 3. Feel free to send me a PM with your phone number and 4 digit security code.
You can find the How To for sending private messages here: https://communities.dish.com/t5/Communities-101/How-To-Send-a-Private-Message/td-p/15039