My angular app is blocked from accessing my .NET core api

registration:1 Access to XMLHttpRequest at 'http://localhost:8080/api/User/register' from origin 'http://localhost:4200' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

builder.Services.AddCors(option =>
{
    option.AddPolicy("AllowMyOrigin", builder =>
    {
        builder.WithOrigins("http://localhost:80");
        //builder.AllowAnyOrigin();
        builder.AllowAnyHeader();
        builder.AllowAnyMethod();
    });
});
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.UseSwagger();
//app.UseSwaggerUI();

app.UseCors("AllowMyOrigin");

app.UseAuthorization();

app.MapControllers();

app.Run();