Invalid Authentication Token Error with Microsoft Graph for token obtained through Azure's built in app services authentication - azure-mobile-services

Question

On the backend of my Azure Mobile App, I am using Azure's built in authentication services to obtain an access token when a user logs on to my app via a Microsoft account. I am successfully obtaining that token.
However, I then attempt to call out to the Microsoft Graph to obtain the authenticated user's name, email, and ID. Azure's log stream shows me this error:
MicrosoftGraphServiceException:
Code: InvalidAuthenticationToken
Message: CompactToken parsing failed with error code: 8004920A
Here is the applicable code:
[MobileAppController]
public class MicrosoftAccountController : ApiController
{
MicrosoftAccountCredentials credentials;
// GET api/<controller>
public async Task<DataObjects.User> Get()
{
if (credentials == null)
{
credentials =
await this.User.GetAppServiceIdentityAsync<MicrosoftAccountCredentials>(this.Request);
var accessToken = credentials.AccessToken;
}
GraphServiceClient graphClient =
new Microsoft.Graph.GraphServiceClient(new DelegateAuthenticationProvider((requestMessage) =>
{
requestMessage.Headers.Authorization =
new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", accessToken);
return Task.FromResult(0);
}));
Microsoft.Graph.User graphuser = await graphClient.Me.Request().GetAsync();
}
Thanks for you help!

Answer 1

According to your description, I assumed that you could directly access your mobile app https://{your-app-name}.azurewebsites.net/.auth/login/microsoftaccount via the browser and login with your MSA. After logged, you could try to access https://{your-app-name}.azurewebsites.net/.auth/me to retrieve the logged user info as follows:
Then, you could retrieve the access_token and try to simulate the request via postman to narrow this issue:
However, I then attempt to call out to the Microsoft Graph to obtain the authenticated user's name, email, and ID.
I assumed that you could call await App.MobileService.InvokeApiAsync("/.auth/me", HttpMethod.Get, null); in your mobile client after user logged to retrieve the user info. I found that you created a custom WebAPI and extracted the token based on the current request and used the graph client to retrieve the user info, I did not check your code, but you could remote debugging your mobile app to troubleshoot with your code.
Moreover, you could follow App Service Token Store for more details about App Service Authentication / Authorization.
UPDATE:
However, I then attempt to call out to the Microsoft Graph to obtain the authenticated user's name, email, and ID. Azure's log stream shows me this error
I checked your code and found that Microsoft Graph targets at graph.microsoft.com, while the MSA login for App Service Authentication/Authorization used the Live SDK. And the Live SDK is deprecated, I did not found any client SDK for consuming the Rest APIs, I assumed that you could just create the WebRequest and access the Live SDK REST API by yourself.