Getting "We couldn't sign you in" error after signing into .NET Core web app using Azure authentication

It sounds like you're encountering a common issue related to Azure authentication in your .NET Core application. The "We couldn't sign you in" error can often be attributed to misconfigurations in your application or the Azure AD setup. Here are some troubleshooting steps you can take:

1. Check Configuration: Ensure that your application settings in Azure AD (like the Redirect URI, Client ID, and Tenant ID) match exactly with what you have in your application. Any mismatch can lead to authentication failures.
2. Review Logs: Enable detailed logging in your application to capture any errors during the authentication process. This can provide insights into what might be going wrong.
3. Network Issues: Since you mentioned different results on localhost versus your test server, ensure that the server is correctly configured to allow traffic to and from Azure AD. Check firewall settings and network configurations.
4. Inspect the Authentication Flow: Use browser developer tools to inspect network requests during the authentication process. Look for any failed requests or error messages that might indicate what is causing the loop or failure.
5. Application Manifest: If you are using Microsoft Entra ID, ensure that the application manifest is correctly configured to allow public clients if necessary. This can be a common source of issues.
6. Consult Documentation: Since you are following a tutorial, double-check each step to ensure nothing was missed, especially regarding the integration of the Index.html.cs code into your existing Home controller.

If you continue to experience issues, consider reaching out to community forums like Stack Overflow or the ASP.NET Core Slack Team for additional support.

References:

• Tutorial: Add sign-in and sign-out to an ASP.NET Core web application for an external tenant
• Secure an ASP.NET Core Blazor Web App with Microsoft Entra ID

it sounds like the web app can not validate the code sent to the reply url. check that the web server has access to the azure oauth server. you may need to change firewall rules. also if the production server is a web farm, you will need to configure data protection services for a farm support.

Program.cs

using Example.Models; using Example2.Models;

using Microsoft.EntityFrameworkCore;

// <ms_docref_import_types>

using Microsoft.AspNetCore.Authorization;

using Microsoft.AspNetCore.Mvc.Authorization;

using Microsoft.Identity.Web;

using Microsoft.Identity.Web.UI;

// </ms_docref_import_types>

var builder = WebApplication.CreateBuilder(args);

IEnumerable<string>? initialScopes = builder.Configuration["DownstreamApi:Scopes"]?.Split(' ');

builder.Services.AddMicrosoftIdentityWebAppAuthentication(builder.Configuration, "AzureAd") .EnableTokenAcquisitionToCallDownstreamApi(initialScopes) .AddDownstreamApi("DownstreamApi", builder.Configuration.GetSection("DownstreamApi")) .AddInMemoryTokenCaches();

// </ms_docref_add_msal>

// Add services to the container.

builder.Services.AddControllersWithViews();

builder.Services.AddDbContext<Test_RRContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

builder.Services.AddDbContext<lansweeperdbContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("LSConnection")));

builder.Services.AddRazorPages().AddMvcOptions(options =>

{ var policy = new AuthorizationPolicyBuilder() .RequireAuthenticatedUser() .Build(); options.Filters.Add(new AuthorizeFilter(policy));

}).AddMicrosoftIdentityUI();

// </ms_docref_add_default_controller_for_sign-in-out>

var app = builder.Build();

// Configure the HTTP request pipeline.

if (!app.Environment.IsDevelopment())

//if (app.Environment.IsDevelopment())

{ app.UseExceptionHandler("/Home/Error"); // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts. app.UseHsts();

}

app.UseHttpsRedirection();

app.UseStaticFiles();

app.UseRouting();

app.UseAuthentication();

app.UseAuthorization();

app.MapRazorPages();

app.MapControllers();

app.MapControllerRoute( name: "default", pattern: "{controller=Home}/{action=Index}");

app.Run();