MercadoPago Checkout Custom - Sandbox - Application_feed

I want to create a payment with the MercadoPago PHP SDK (personalized checkout), I also complete the "application_fee" field.

$mp = new MP('TEST-3449330551625292-111409-78d0be0245463f74bccc7c6b7203196b__LD_LA__-XXXXX');

$payment_data = array(
    "transaction_amount" => 100,
    "token" => "442188e1b5510628aa7b9d4f5289ce56",
    "description" => "Title of what you are paying for",
    "installments" => 1,
    "payer" => array (
        "email" => "[email protected]"
    ),
    "payment_method_id" => "visa",
    "application_fee" => 2.56 
);
$payment = $mp->post("/v1/payments", $payment_data);

I am charging with the access_token of a "seller" user who authorized the app. But in response I get You can not use application_fee with this payment. - 2059: You can not use application_fee with this payment .

As far as I could find on the Internet (very little) this happens when instead of using the access_token the seller uses the user's creator of the app. This would not be the case.

I clarify that taking PHP out of the application_fee field, everything is about 10.

Could it be that when you are in sandbox mode you can not create commission payments? Did something similar happen to someone? What else could it be?

Thank you.