Here is my program.cs class:

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddTransient<IUserService, UserService>();


builder.Services.AddTransient<IUserRepository, UserRepository>();

#region IAUECManager Database Connection

builder.Services.AddDbContext<IAUECManagerDbContext>(options =>
{
  options.UseSqlServer(builder.Configuration.GetConnectionString("IAUECManagerConnectionString"));
});

#endregion

#region JWT Authentication

 //TODO Change JWT Secret Key
var jwtSecretKey = "something that should be change in the future";

builder.Services.AddHttpClient();


builder.Services.AddAuthentication(option =>
{
    option.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    option.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
    .AddJwtBearer(option =>
    {
    option.RequireHttpsMetadata = false;
    option.SaveToken = true;
    option.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuerSigningKey = true,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(jwtSecretKey)),
        ValidateIssuer = false,
        ValidateAudience = false
    };
});

#endregion

//services.AddCors();
builder.Services.AddCors(o => o.AddPolicy("MyPolicy", builder => {
    builder.AllowAnyHeader()
        .AllowAnyMethod()
        .AllowAnyOrigin();
}));

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}


app.UseCors("MyPolicy");

app.UseHttpsRedirection();


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

app.MapControllers();

app.Run();

Why when I want to send a request from ajax which is in my UI project that is including in the same solution with my api project it says:

Access to XMLHttpRequest at 'https://localhost:7039/api/V1/Users/Register' from origin 'https://localhost:44323' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.