preflight request doesn't pass access control

[DTHerrera]

Hi, after register a nemiro.oAuth API in my project, when a try to signing user with FaceBook or Twitter i get the followin mesagges:

api.twitter.com/oauth/authorize?oauth_token=DdapZwAAAAAA4_VyAAABY19RKB0:1 Failed to load resource: the server responded with a status of 400 ()
Home:1 Failed to load https://api.twitter.com/oauth/authorize?oauth_token=DdapZwAAAAAA4_VyAAABY19RKB0: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://localhost:44305' is therefore not allowed access. The response had HTTP status code 400.

Home:1 Failed to load https://www.linkedin.com/uas/oauth2/authorization?client_id=8649u8izdndqu5&response_type=code&state=fc48a1908548404caffb0338018ffd7f&scope=r_basicprofile%20r_emailaddress&redirect_uri=https%3A%2F%2Flocalhost%3A44305%2FHome%2FExternalLoginResult: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://localhost:44305' is therefore not allowed access.

Home:1 Failed to load https://www.facebook.com/dialog/oauth?client_id=225631291319901&response_type=code&state=a93f3e7389a241489483bd8f4ca5b8ec&scope=public_profile%2Cemail&redirect_uri=https%3A%2F%2Flocalhost%3A44305%2FHome%2FExternalLoginResult: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://localhost:44305' is therefore not allowed access.

in mi project i used the nemiro.OAuth like this:

[Route("LoginExterno/{provider}")]
[HttpPost]
[AllowAnonymous]
//[HttpGet]

    public async Task<IHttpActionResult> LoginExterno(string provider = "")
    {
        if (string.IsNullOrWhiteSpace(provider))
        {
            ModelState.AddModelError("", "Se requiere el provedor de autenticación");
            return BadRequest(ModelState);
        }

        //var returnUrl = new Uri("/Home/ExternalLoginResult", UriKind.Relative).AbsoluteUri;  //
        //return Redirect(Url.Content("~/") + "#error=" + Uri.EscapeDataString("/Home/ExternalLoginResult"));
        string returnUrl =  Url.Content("~/") + "Home/ExternalLoginResult";
         OAuthWeb.RedirectToAuthorization(provider, returnUrl);

        return Ok();
    }

could you help me please?, what I do wrong in the implementation.

thenak in advance.