Angular 2 Token: Response for preflight has invalid HTTP status code 400
<p>I have an Angular2/TypeScript application running i Visual Studio Code.</p>

<p>An API running in VS 2015. This is the API project: <a href="http://www.asp.net/web-api/overview/security/individual-accounts-in-web-api" rel="noreferrer">http://www.asp.net/web-api/overview/security/individual-accounts-in-web-api</a></p>

<p>I can use the API and create new users, but when I try to login(Use the Token function), then I get the following error:
<strong>XMLHttpRequest cannot load <a href="https://localhost:44305/Token" rel="noreferrer">https://localhost:44305/Token</a>. Response for preflight has invalid HTTP status code 400</strong></p>

<p>The header looks like this:</p>

<pre><code>Request URL:https://localhost:44305/Token
Request Method:OPTIONS
Status Code:400 
Remote Address:[::1]:44305
Response Headers
cache-control:no-cache
content-length:34
content-type:application/json;charset=UTF-8
date:Wed, 10 Aug 2016 19:12:57 GMT
expires:-1
pragma:no-cache
server:Microsoft-IIS/10.0
status:400
x-powered-by:ASP.NET
x-sourcefiles:=?UTF-8?B?QzpcQ2hlY2tvdXRcQVBJXzJ2czJcQVBJXEFQSVxUb2tlbg==?=
Request Headers
:authority:localhost:44305
:method:OPTIONS
:path:/Token
:scheme:https
accept:*/*
accept-encoding:gzip, deflate, sdch, br
accept-language:en-US,en;q=0.8,da;q=0.6,nb;q=0.4
access-control-request-headers:authorization
access-control-request-method:POST
cache-control:no-cache
origin:http://evil.com/
pragma:no-cache
referer:http://localhost:3000/signin
user-agent:Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36
</code></pre>

<p>My angular service looks like this:</p>

<pre><code> loginAccount(account: Account): Observable&lt;string&gt; {        
    var obj = { Email: account.Email, Password: account.Password, grant_type: 'password' };
        let headers = new Headers({ 'Content-Type': 'application/json' });
        let options = new RequestOptions( {method: RequestMethod.Post, headers: headers });

        let body = JSON.stringify(obj);
        console.log('loginAccount with:' + body);

         return this._http.post('https://localhost:44305/Token',  body, options)
                             .map(this.extractData)
                             .catch(this.handleError);
}
</code></pre>

<p>When I use the AJAX funtions that a in the API project: <a href="http://www.asp.net/web-api/overview/security/individual-accounts-in-web-api" rel="noreferrer">http://www.asp.net/web-api/overview/security/individual-accounts-in-web-api</a> then it works fine ?? What am I doing wrong in the Angular POST request ?</p>