Program.cs

using Swashbuckle.AspNetCore.SwaggerGen;
using Swashbuckle.AspNetCore.SwaggerUI;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Services.AddCors(options =>
{
    options.AddPolicy("AllowAll",
        builder => builder.AllowAnyOrigin()
            .AllowAnyMethod()
            .AllowAnyHeader());
});

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseStatusCodePages(async statusCodeContext =>
{
    var response = statusCodeContext.HttpContext.Response;
    if (response.StatusCode == 404)
    {
        response.ContentType = "application/json";
        await response.WriteAsync("{\"error\":\"Not Found\",\"message\":\"The requested resource was not found.\"}");
    }
});

app.UseCors("AllowAll");
app.UseAuthorization();
app.MapControllers();

app.Run();