Error trying to use api.createUser(userData, callback) for connection:sms (passwordless)

Using node-auth 0.8.2

I may be using this method incorrectly but tried to follow the parameters mentioned in Passwordless Connections for the /users POST endpoint and I keep getting passed an error object with this message to my callback :

 ApiError: User must have one of the following identifier fields: user_id | _id | id

More details:

The SMS is being sent via Twillio and my phone received the verification code generated by Auth0. so the Twillio connection is correctly configured on Auth0 connections.
The user is not listed on Auth0 Dashboard for the app.
Even if I pass an attribute user_id, id, or _id on the userParams to api.createUser this error keeps coming with the same message.

The call to api.createUser is being made like this:

    // api = new Auth0({.....})
    api.createUser({
      connection: "sms",
      email_verified: false,
      phone_number: "+541155555555"
    }, function(err, user) {
      if (err) {
        var errorstring = util.format("Error creating user : %s", err.toString());
        return res.status(500).json({
          message: errorstring
        });
      }
      res.json(user);
    });

auth0 / node-auth0

Error trying to use api.createUser(userData, callback) for connection:sms (passwordless) #32