ASP.NET Web Api在获取跨源令牌时出现问题

我在使用跨源代码从前端（Node.js和Ajax）登录Web Api时遇到了一些问题。我得到以下错误：

XMLHttpRequest cannot load http://localhost:61102/Token. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' is therefore not allowed access. The response had HTTP status code 500.

只有当我尝试调用/Token登录时才会出现这个问题。我可以访问其他路由并完美注册。这是我的代码：

Startup.cs:

public void Configuration(IAppBuilder app)
{
    HttpConfiguration config = new HttpConfiguration();
    ConfigureAuth(app);
    WebApiConfig.Register(config);
    app.UseCors(CorsOptions.AllowAll);
    app.UseWebApi(config);
}

Startup.Auth.cs:

public void ConfigureAuth(IAppBuilder app)
{
    // Configure the db context and user manager to use a single instance per request
    app.CreatePerOwinContext(ApplicationDbContext.Create);
    app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
    // Enable the application to use a cookie to store information for the signed in user
    // and to use a cookie to temporarily store information about a user logging in with a third party login provider
    app.UseCookieAuthentication(new CookieAuthenticationOptions());
    app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);
    // Configure the application for OAuth based flow
    PublicClientId = "self";
    OAuthOptions = new OAuthAuthorizationServerOptions
    {
        TokenEndpointPath = new PathString("/Token"),
        Provider = new ApplicationOAuthProvider(PublicClientId),
        AuthorizeEndpointPath = new PathString("/api/Account/ExternalLogin"),
        AccessTokenExpireTimeSpan = TimeSpan.FromDays(14),
        // In production mode set AllowInsecureHttp = false
        AllowInsecureHttp = true
    };
    // Enable the application to use bearer tokens to authenticate users
    app.UseOAuthBearerTokens(OAuthOptions);
}      

我已经将context.OwinContext.Response.Headers.Add("Access-Control-Allow-Origin", new[] { "*" });放入ApplicationOAuthProvider.cs 中的GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)中

很长一段时间以来，我一直在努力寻找答案，但却偶然发现了很多不同的答案，这些答案对我来说都不起作用。我不确定出了什么问题。

更新-添加了我的ajax脚本

import {URL} from '../constants/AuthConstants';
import request from 'reqwest';
import history from './HistoryService';
let router = null;
class AuthService {
    login(email, password) {
        console.log(URL.LOGIN);
        var grant_type = 'password';
        return request({
            url: URL.LOGIN,
            method: 'POST',
            crossOrigin: true,
            content-Type
            data: {
                grant_type, email, password
            },
            success: function(response) {
                console.log("Yay! Login", response);
            },
            error: function(response) {
                console.log("Error! Login", response);
            }
        });
    }
}