Jquery $.Ajax() keep getting 401 response

问题

I'm trying to get JSON through an API but it keeps giving me

Response for preflight has invalid HTTP status code 401

This is my code

        $.ajax({
        beforeSend: function (request)
        {
            request.withCredentials = true;
            request.setRequestHeader("Authorization", "Basic" +  btoa("usernamehere:keyhere"));
        },
        crossDomain: true,
        contentType: 'application/json',
        url: url,

With the username and key different ofcourse. I've tried without btoa, i've tried using headers: and I've edited the CORS. But nothing works, it just keeps throwing the same error over and over eventhough I can login with the credentials if I go to the url.

回答1:

contentType: 'application/json'

Was not allowed, that fixed it.

来源：https://stackoverflow.com/questions/36764742/jquery-ajax-keep-getting-401-response