I have been trying to consume a simple web service crated with GeneXus, it should receive a "nPais" variable (integer) and respond an object with the text property based on the given number. It just doesn't work. I have confirm that the service work by testing it with soapUI (adding the WSDL), but when trying to consume it with postman it responds the correct structure, but with the text property empty.

This is my source tab from the WS.

&sdtServicio = New()
&Servicio.SetEmpty()
Do Case
    Case &nPais = 1
        &sdtServicio.Texto = "Hola México"
    Case &nPais = 2
        &sdtServicio.Texto = "Hola Argentina"
    Otherwise
        &sdtServicio.Texto = "HOLA MUNDO"
Endcase

This is on rules tab

Parm(in:&nPais, out:&sdtServicio);

And here is how I have been trying to consume the service on JS.

function getGreeting(value) {
    var myHeaders = new Headers();
    myHeaders.append("Content-Type", "application/json");
    myHeaders.append("Cookie", "GX_CLIENT_ID=54f383cc-0719-444d-a252-c8799c1202a0");

    var raw = JSON.stringify({
    "nPais": 1
    });

    var requestOptions = {
        method: 'POST',
        headers: myHeaders,
        body: raw,
        redirect: 'follow'
    };

    fetch("http://localhost:8080/PotentorDesaPotDesa/rest/WSHolaMundo", requestOptions)
    .then(response => response.text())
    .then(result => console.log(result))
    .catch(error => console.log('error', error));
}

This is the response I get.

{"sdtServicio":{"Texto":""}}