If you are using .NET with OpenID Connection (OIDC), we suggest the following.

.NET file changes

Have a program.cs/startup.cs file, something like this:

services.AddAuthentication(options =>
{
    options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
})
.AddCookie()
.AddOpenIdConnect(options =>
{
    options.Authority = Configuration["Kinde:Domain"];
    options.ClientId = Configuration["Kinde:ClientId"];
    options.ClientSecret = Configuration["Kinde:ClientSecret"];
    options.ResponseType = "code";
    options.Scope.Add("openid");
    options.Scope.Add("profile");
    options.SaveTokens = true;
    options.GetClaimsFromUserInfoEndpoint = true;
    // Set other necessary options
});

Have a middleware for pipeline program.cs or configure method of startup.cs:

app.UseAuthentication();
app.UseAuthorization();

Then the authentication should be handled automatically:

[HttpGet]
public async Task<IActionResult> Callback()
{
    // This should be handled automatically by the OpenID Connect middleware
    // You can perform additional actions here if necessary
    return LocalRedirect(Url.Content("~/")); // Redirect to home or other page
}

Then you can check it with:

@inject AuthenticationStateProvider AuthenticationStateProvider

protected override async Task OnInitializedAsync()
{
    var authState = await AuthenticationStateProvider.GetAuthenticationStateAsync();
    var user = authState.User;

    if (user.Identity.IsAuthenticated)
    {
        // User is authenticated
    }
}

Other

Here are other tips we recommend:

1. Install the Microsoft.AspNetCore.Authentication.OpenIdConnect from NuGet.
2. Add https://localhost:7040/signin-oidc (port might be different) as a callback URL in your Kinde backend application