AuthenticationBuilder does not contain a definition for AddAzureAd

Question

Im following a tutorial from here and trying to enable OpenId Connect using Azure Ad and here's the code that I am trying to add to the Startup.cs file.

    services.AddAuthentication(sharedOptions =>
        {
            sharedOptions.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
            sharedOptions.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
        })
        .AddAzureAd(options => Configuration.Bind("AzureAd", options))
        .AddCookie();

But it has red underline for AddAzureAd and shows this error message:

'AuthenticationBuilder' does not contain a definition for 'AddAzureAd' and no accessible extension method 'AddAzureAd' accepting a first argument of type 'AuthenticationBuilder' could be found (are you missing a using directive or an assembly reference?)

Steps I have tried:

1. Clean and rebuild the solution
2. restart visual studio

But it doesnt fix the issue. Anyone knows what's the other reason that causes this?

Answer 1

I had the exact same loss of time with something as stupid as not adding the reference. The answer to this question would be along the lines of:

 dotnet add package Microsoft.AspNetCore.Authentication.AzureAD.UI --version 2.2.0

Notice that you may have added another reference related to authentication but not the one you are having the problem about.

Answer 2

I had to add a using statement to my Startup file.

using Microsoft.AspNetCore.Authentication;