Querying Metadata Basic Auth Handler never called

I am enabling basic authentication and JwtBearer authentication mechanism. When querying metadata JwtBearer validation works but Basic Auth handler is never called.
How to authenticate a user using basic authentication when querying metadata?

Remark: Querying controller with [Authorised] attribute trigger HandleAuthenticateAsync

Startup.cs

//Add Authentication
           services.AddAuthentication()
               .AddJwtBearer(JwtBearerDefaults.AuthenticationScheme, (o) =>
               {
                   o.TokenValidationParameters = new TokenValidationParameters()
                   {
                       IssuerSigningKey = TokenAuthOption.Key,
                       ValidAudience = TokenAuthOption.Audience,
                       ValidIssuer = TokenAuthOption.Issuer,
                       ValidateIssuerSigningKey = true,
                       ValidateLifetime = true,
                       ValidateIssuer = true,
                       ValidateAudience = true,
                       ClockSkew = TimeSpan.FromMinutes(0)
                   };
               })
               .AddScheme<AuthenticationSchemeOptions, BasicAuthenticationHandler>("Basic", null);

           //Add Authorization
           services.AddAuthorization((o) =>
           {
               // define Basic and Bearer default auth
               o.DefaultPolicy = new AuthorizationPolicyBuilder(new string[] { JwtBearerDefaults.AuthenticationScheme, "Basic" })
               .RequireAuthenticatedUser()
               .Build();

               //Only JwtBearer
               var onlyJwtBearerSchemePolicyBuilder = new AuthorizationPolicyBuilder(JwtBearerDefaults.AuthenticationScheme);
               o.AddPolicy(JwtBearerDefaults.AuthenticationScheme, onlyJwtBearerSchemePolicyBuilder
                   .RequireAuthenticatedUser()
                   .Build());

               //Only Basic
               var onlyBasicSchemePolicyBuilder = new AuthorizationPolicyBuilder("Basic");
               o.AddPolicy("Basic", onlyBasicSchemePolicyBuilder
                   .RequireAuthenticatedUser()
                   .Build());
           });

BasicAuthenticationHandler.cs

public class BasicAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
    {
        public BasicAuthenticationHandler(
           IOptionsMonitor<AuthenticationSchemeOptions> options,
           ILoggerFactory logger,
           UrlEncoder encoder,
           ISystemClock clock
           ) : base(options, logger, encoder, clock)
        {
        }

        protected override Task<AuthenticateResult> HandleAuthenticateAsync()
        {
            var authHeader = Request.Headers["Authorization"].ToString();
            if (authHeader != null && authHeader.StartsWith("basic", StringComparison.OrdinalIgnoreCase))
            {
                var token = authHeader.Substring("Basic ".Length).Trim();
                var credentialstring = Encoding.UTF8.GetString(Convert.FromBase64String(token));
                var credentials = credentialstring.Split(':');
                if (credentials[0] == "admin" && credentials[1] == "admin")
                {
                    //Build Claims
                    //var Claims = new List<Claim>();
                    //Claims.Add(new Claim(ClaimTypes.NameIdentifier, UserId.ToString()));
                    //Claims.Add(new Claim(ClaimTypes.Name, Username));
                    //Claims.Add(new Claim(ClaimTypes.Email, UserEmail));
                    //foreach (var userRole in UserRoles)
                    //    Claims.Add(new Claim(ClaimTypes.Role, userRole));

                    var claims = new[] { new Claim("name", credentials[0]), new Claim(ClaimTypes.Role, "Admin") };
                    var identity = new ClaimsIdentity(claims, "Basic");
                    var claimsPrincipal = new ClaimsPrincipal(identity);
                    return Task.FromResult(AuthenticateResult.Success(new AuthenticationTicket(claimsPrincipal, Scheme.Name)));
                }

                Response.StatusCode = 401;
                Response.Headers.Add("WWW-Authenticate", "Basic realm=\"ami.com\"");
                return Task.FromResult(AuthenticateResult.Fail("Invalid Authorization Header"));
            }
            else
            {
                Response.StatusCode = 401;
                Response.Headers.Add("WWW-Authenticate", "Basic realm=\"ami.com\"");
                return Task.FromResult(AuthenticateResult.Fail("Invalid Authorization Header"));
            }
        }
    }

`