PlatformPlugin exception getting app-only token in ASP.NET Core

[DianeD]

I'm trying to create an ASP.NET Core app that uses MSAL for the client credentials flow.

I get the following exception when trying to get an access token:

NullReferenceException: Object reference not set to an instance of an object.
Microsoft.Identity.Client.Internal.PlatformPlugin.LoadPlatformSpecificAssembly()

Authentication is modeled on active-directory-dotnet-webapp-openidconnect-aspnetcore-v2
Authorization is modeled on active-directory-dotnet-daemon-v2

My app is registered with the Mail.Read Application permission. Here's the code that throws the exception:

string authority = $"https://login.microsoftonline.com/{ tenantId }/v2.0";
ConfidentialClientApplication client = new ConfidentialClientApplication(
    authority,
    appId,
    redirectUri,
    new ClientCredential(appSecret),
    null); //new TokenCache());

AuthenticationResult authResult = await client.AcquireTokenForClient(
    new string[] { "https://graph.microsoft.com/.default" }, null); //"Mail.Read"
return authResult.Token;

I've tried variations in the project.json file. Right now it's:

{
  "userSecretsId": ...,

  "dependencies": {
    "BundlerMinifier.Core": "2.2.306",
    "Microsoft.AspNetCore.Mvc": "1.1.0",
    "Microsoft.AspNetCore.Authentication.Cookies": "1.1.0",
    "Microsoft.AspNetCore.Authentication.OpenIdConnect": "1.1.0",
    "Microsoft.AspNetCore.Diagnostics": "1.1.0",
    "Microsoft.AspNetCore.Routing": "1.1.0",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.1.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.1.0",
    "Microsoft.AspNetCore.Session": "1.1.0",
    "Microsoft.AspNetCore.SignalR.Server": "0.2.0-*",
    "Microsoft.AspNetCore.WebSockets": "0.2.0-*",
    "Microsoft.AspNetCore.StaticFiles": "1.1.0",
    "Microsoft.Extensions.Caching.Memory": "1.1.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.1.0",
    "Microsoft.Extensions.Configuration.Json": "1.1.0",
    "Microsoft.Extensions.Configuration.UserSecrets": "1.1.0",
    "Microsoft.Extensions.Logging": "1.1.0",
    "Microsoft.Extensions.Logging.Console": "1.1.0",
    "Microsoft.Extensions.Logging.Debug": "1.1.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.1.0",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.1.0",
    "Microsoft.Graph": "1.2.0",
    "NuGet.CommandLine": "3.4.3",
    "Microsoft.AspNetCore.Http.Abstractions": "1.1.0",
    "Microsoft.Identity.Client": "1.0.304142221-alpha",
    "Microsoft.NETCore.App": {
      "version": "1.1.0",
      "type": "platform"
    }
  },

  "tools": {
  },

  "frameworks": {
    "netcoreapp1.1": {
      "imports": [
        "dotnet5.6",
        "dnxcore50",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimes": {
    "win10-x64": {}
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "**/*.cshtml",
      "appsettings.json",
      "web.config"
    ]
  },

  "scripts": {
    "prepublish": [ "bower install", "dotnet bundle" ],
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

[kpanwar]

this problem will not occur with the next release as we will move to a single binary.