title: Connection Issues when using AcquireTokenAsync() in Xamarin Forms Windows App with Azure AD B2C and custom policy
body: <p>I am using MSAL to connect my Xamarin.Forms-Windows 8.1-App to Azure AD B2C with a custom SignInSignUp-policy (to login the user by using a custom E-Mail address and a password). The "normal" authentication against Azure AD (without custom policy) works fine, but when I use the policy, the message "We can't connect to the service you need right now. Check your network connection or try this again later." appears everytime after providing the credentials (directly within the dialog). Since the dialog does not finish correctly, I am not retrieving any exception or AuthenticationResult and so I am not able to determine the concrete issue (the internet connection itself is not the problem).</p>
  
  <p>Note: I also tried this in a Xamarin.Forms-UWP-App which leads me to the same issue. Under iOS, it is working fine and the dialog finishes and closes correctly.</p>
  
  <p>NuGet Versions:
  MSAL (Microsoft.Identity.Client): 1.0.304142201-alpha
  Xamarin.Forms: 2.3.2.118-pre1</p>
  
  <p>Thats my code (simplified):</p>
  
  <pre><code>var clientId = "{My application's ClientId}";
  var redirectUri = "urn:ietf:wg:oauth:2.0:oob";
  var authority = "https://login.microsoftonline.com/{My Azure AD B2C}";
  string[] scopes = { clientId };
  var policy = "{My SignUpSignIn policy}";
  
  var clientApplication = new PublicClientApplication (authority, clientId);
  clientApplication.RedirectUri = redirectUri;
  
  var result = await this.clientApplication.AcquireTokenAsync(scopes, string.Empty, UiOptions.SelectAccount, string.Empty, null, authority, policy);
  </code></pre>
  
  <p>Any ideas on this?</p>
  
  <p>Thanks in advance!</p>
  
  <p>Regards,<br>
  Marcel</p>