private AcquireAccessTokenResult InternalAcquireAccessToken(string AuthorizationCode)
{
// Build a POST body.
string postBody = "grant_type=authorization_code" +
"&Resource=" + System.Web.HttpUtility.UrlEncode(Util.ConvertResourceEnumToUri(Resource)) +
"&client_id=" + ClientID +
"&code=" + AuthorizationCode +
"&redirect_uri=" + System.Web.HttpUtility.UrlEncode(RedirectUri);
string endPoint = "https://login.microsoftonline.com/" + TenantName.Replace("@", ".") + "/oauth2/token";
return(AcquireAccessToken(postBody, endPoint));
}