Can not log in into my Mobile App when the Web API is behind a Front Door

Ihor Kuliiev 21

Hello,

My Mobile App (Xamarin Native) uses WebAuthenticator for authentication with different identity providers - Microsoft, Google, Facebook, Twitter.

There is an AuthenticationController on my Web API the WebAuthenticator makes a call to. After that a user is redirected to a provider's login page. Once authenticated, the second call is made to the AuthenticationController where a custom access token is generated for the user, and they are logged in into the Mobile App.

The Web API is deployed on Azure App Service.

If I use an Azure Front Door URL (the original Web API URL is behind it), then after entering credentials the second call to the AuthenticationController never happens. Users see just a blank white screen.

I will be grateful for any help or adviсe.

Thank you.

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 26,221 Reputation points Microsoft Vendor

2023-03-13T06:03:32.4666667+00:00

You are using Xamarin.Essentials： Web Authenticator, right? I'm not sure this is a server side issue or client side(app) issue. Can you provide some code snippets? And what's the detailed Xamarin.iOS version and Xamarin.Forms version? On which device/platform does the user see just a blank white screen?
GitaraniSharma-MSFT 47,316 Reputation points Microsoft Employee

2023-03-13T11:21:21.3466667+00:00

Hello @Ihor Kuliiev ,

To troubleshoot the exact issue here, we will need a specialized 1:1 session, where a support engineer can have a screen share session to pinpoint the issue. So, if you have a support plan, I request you file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.

Regards,

Gita
Ihor Kuliiev 21 Reputation points

2023-03-13T14:37:15.9266667+00:00
To be more specific, I use the flow exactly as described in this article:

https://learn.microsoft.com/en-us/xamarin/essentials/web-authenticator?context=xamarin%2Fandroid&tabs=android

The mobile application calls this method and the authResult is never returned (users see a white screen at this time):

var authResult = await WebAuthenticator.AuthenticateAsync(new WebAuthenticatorOptions { Url = url, CallbackUrl = callbackUrl, PrefersEphemeralWebBrowserSession = true });

Actually, the flow gets stuck at this step, when an External Provider reaches out back to my MobileAuthController:

Want to highlight one more time, that if I use my original Web API URL (not the Front Door URL) everything works pretty fine.
GitaraniSharma-MSFT 47,316 Reputation points Microsoft Employee

2023-03-17T11:18:11.26+00:00

@Ihor Kuliiev , it is difficult to troubleshoot this issue without looking at the actual setup/requests and pulling the backend logs.

Hence, as I mentioned above, to troubleshoot the exact issue here, we will need a specialized 1:1 session, where a support engineer can have a screen share session to pinpoint the issue. So, if you have a support plan, I request you file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.