Kinvey problem login

const kinveyUsername = "guest";
const kinveyPasssword = "guest";
const appKey = "kid_Syz-eCp-H";
const appSecret = "853929bb0bfd44768b2972fcc9c74253"

const baseUrl = 'https://baas.kinvey.com/appdata/kid_Syz-eCp-H/books';

function login() {
    let url = 'https://baas.kinvey.com/user/kid_Syz-eCp-H/login'

    let userData = {
        username: "guest",
        password: "guest"
    }

    let headers = {
        method: "POST",
        mode: "no-cors",
        credentials: "include",
        body: JSON.stringify(userData),
        headers: {
            'Content-Type': 'application/json',
			//Same as "Authorization": "Basic " + btoa(appKey + ':' + appSecret);
            "Authorization": "Basic a2lkX1N5ei1lQ3AtSDo4NTM5MjliYjBiZmQ0NDc2OGIyOTcyZmNjOWM3NDI1Mw=="
        }
    }

    fetch(url, headers)
        .then(res => res.json())
        .then(data => console.log(data))
        .catch(error => console.error(error));

}

login();