Call WEB Services SAP IRPA

Hi, I am having trouble using the custom script to get data from an API, I tested it by POSTMAN and it worked...
I need to get the token to go to the next step of the process, but I can't, the API documentation tells me to use this request method, the token. To use this APIs you need to use a Bearer token, which can be obtained through an API, passing a user and password to an endpoint, in this model:

to do this I converted the above code to javascript returning this code below, but the POST request is returning blank, but if I do it with POSTMAN it works, can you help me?

I have downloaded the web services from the store to try to use it, but I can't tell which automation is the most appropriate for this process

async function fetchToken() {
  const requestOptions = {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      role: 'enterprise',
      username: '',
      password: ''
    })
  };
  try {
    const response = await irpa_core.request.call('https://api.trizy.com.br/iam/auth', requestOptions);
    return response;   
  } catch (error) {
    return error;
  }
}
let response = await fetchToken();
return response.headers;