Policy based authorization on razor pages

I trying to set up policy-based authorization on razor pages on Core2.1.

I have set up the policy and decorated the razor page with the authorize attribute. I cannot figure what am I doing wrong or if something else needs to be done, but I cannot get the page to authorize. It always gives me

No web page was found for the web address:

localhost/ADENETCore/Account/AccessDenied?ReturnUrl=%2FADENETCore%2FContact

Can you please point me in the right direction?

ConfigureServices:

services.AddAuthorization(options =>
                {
                    options.AddPolicy("AtLeast21", policy =>
                        policy.Requirements.Add(new MinimumAgeRequirement(21)));
                });
            services.AddMvc().AddRazorPagesOptions(options =>
                    {
                        options.Conventions.AuthorizePage("/Contact", "AtLeast21"); // with policy
                    })
                .SetCompatibilityVersion(CompatibilityVersion.Version_2_1).AddSessionStateTempDataProvider();

Configure:

    app.UseAuthentication();
    app.UseMvc();

Policy Requirement:

    public class MinimumAgeRequirement : IAuthorizationRequirement
    {
     public int MinimumAge { get; private set; }

     public MinimumAgeRequirement(int minimumAge)
     {
      MinimumAge = minimumAge;
     }
    }

Policy Handler:

public class MinimumAgeHandler : AuthorizationHandler<MinimumAgeRequirement>
        {
            protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
                                                           MinimumAgeRequirement requirement)
            {
    context.Succeed(requirement);
     return Task.CompletedTask;

    }
}

Razor Page:

[Authorize(Policy = "AtLeast21")]
public class ContactModel : PageModel  

It is redirecting to the Account/AccessDenied page