question

Hi there, I'm using the Sell API to publish an offer on my test seller account that I've created on the sandbox site. I created business policies (fulfillment, payment, return), I created a location, an inventory item. I also created an offer and I can successfully retrieve offer information from the offerId. When I pass the offerId to the request for publishing the offer, I receive this warning:

object(stdClass)#1 (1) {
  ["errors"]=>
  array(1) {
    [0]=>
    object(stdClass)#2 (5) {
      ["errorId"]=>
      int(25002)
      ["domain"]=>
      string(13) "API_INVENTORY"
      ["subdomain"]=>
      string(7) "Selling"
      ["category"]=>
      string(7) "REQUEST"
      ["message"]=>
      string(190) "A user error has occurred. Non hai specificato se sei un privato o un'azienda. Senon specifichi il tipo di account non potrai effettuare vendite. Aggiorna i dati relativi alla registrazione."
    }
  }
}

And I don't know how to set up my test account. If I follow this eBay guide, the Sandbox keeps me returning to the home. How can I publish the offer? Thanks in advice!