AspNetCore 2.1 Bearer Token Authentication - Current user is empty

I've an application that requests a token when the user signs in. That token is then passed with the following header:

Authorization: Bearer <TOKEN>

I've the following code on my startup.cs (aspnet core 2.1):

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvcCore()
            .SetCompatibilityVersion(CompatibilityVersion.Latest)
            .AddFormatterMappings()
            .AddJsonFormatters()
            .AddCors()
            .AddAuthorization(o =>
            {
                o.DefaultPolicy = new AuthorizationPolicyBuilder(JwtBearerDefaults.AuthenticationScheme)
                 .RequireAuthenticatedUser()
                 .Build();
            });

    /* Code... */

    ConfigureAuthentication(services);

    /* Code... */
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UseAuthentication()
       .UseMiddleware<ExceptionMiddleware>(container)
       .UseCors(x =>
       {
           x.WithOrigins("*")
           .AllowAnyMethod()
           .AllowCredentials()
           .AllowAnyHeader()
           .Build();
       });

    /* Code... */
}

private void ConfigureAuthentication(IServiceCollection services)
{
    services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        options.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;
        options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    })
    .AddJwtBearer(options =>
    {
        var tokenProvider = new HumbleTokenProvider(container);
        options.TokenValidationParameters = tokenProvider.GetValidationParameters();
        options.RequireHttpsMetadata = false;
    });
}

To create tokens when the user sign in, I've TokenProvider service:

public class RsaJwtTokenProvider : ITokenProvider
{
    readonly IConfiguration configuration;
    readonly IDateFactory dateFactory;

    readonly RsaSecurityKey _key;
    readonly string _algorithm;
    readonly string _issuer;
    readonly string _audience;

    public RsaJwtTokenProvider(
            IConfiguration configuration,
            IDateFactory dateFactory
        )
    {
        this.configuration = configuration;
        this.dateFactory = dateFactory;

        var parameters = new CspParameters { KeyContainerName = configuration.GetSection("TokenAuthentication:SecretKey").Value };
        var provider = new RSACryptoServiceProvider(2048, parameters);

        _key = new RsaSecurityKey(provider);

        _algorithm = SecurityAlgorithms.RsaSha256Signature;
        _issuer = configuration.GetSection("TokenAuthentication:Issuer").Value;
        _audience = configuration.GetSection("TokenAuthentication:Audience").Value;
    }

    public (string Token, int Expires) CreateToken(string userName, string UserId)
    {
        JwtSecurityTokenHandler tokenHandler = new JwtSecurityTokenHandler();

        var claims = new List<Claim>()
        {
            new Claim(ClaimTypes.NameIdentifier, UserId),
            new Claim(ClaimTypes.Name, userName)
        };

        ClaimsIdentity identity = new ClaimsIdentity(claims, "jwt");

        int expiresIn = int.Parse(configuration.GetSection("TokenAuthentication:Validaty").Value);
        DateTime expires = dateFactory.Now.AddMinutes(expiresIn).ToUniversalTime();
        SecurityToken token = tokenHandler.CreateJwtSecurityToken(new SecurityTokenDescriptor
        {
            Audience = _audience,
            Issuer = _issuer,
            SigningCredentials = new SigningCredentials(_key, _algorithm),
            Expires = expires,
            Subject = identity
        });

        return (tokenHandler.WriteToken(token), expiresIn);
    }

    public TokenValidationParameters GetValidationParameters()
    {

        return new TokenValidationParameters
        {
            // The signing key must match!
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = _key,

            // Validate the JWT Issuer (iss) claim
            ValidateIssuer = true,
            ValidIssuer = _issuer,
            // Validate the JWT Audience (aud) claim
            ValidateAudience = true,
            ValidAudience = _audience,

            // Validate the token expiry
            ValidateLifetime = true,
            // If you want to allow a certain amount of clock drift, set that here:
            ClockSkew = TimeSpan.Zero
        };
    }
}

As you can see, TokenValidationParameters used in AddJwtBearer is provided by the code above GetValidationParameters.

My first perception on this, was that none of the startup authorization/authentication methods checked for the token, or at least I'm not providing it besides the TokenValidationParameters.

I assumed that it worked because of the Token composition and the service would decompose it to extract the current user and insert it into Identity.

However, when I call userManager.GetUserId(user) it returns null.

public string CurrentUser
{
    get
    {
        var user = accessor.HttpContext?.User;
        if (user != null)
            return userManager.GetUserId(user);
        return null;
    }
}

The content of user is the following:

What am I doing wrong?

Screenshot Claims (Token creation)

Update

With the help of Mohammed Noureldin I've discovered that I didn't have claims in my CurrentUser property.

After putting [Authorize] in my controller it started working. However, I need it to work on anonymous actions too... Any idea?