Need help debugging a tiny console app on server

services.AddOptions<SysConfig>()
    .Configure<IConfiguration>((options, configuration) => configuration.Bind(SysConfig.SectionName, options))
    .Validate(options => options.Port is not default(int), $"{nameof(SysConfig.Port)} is not defined!")

.Configure<IConfiguration>((options, configuration) =>
{
    IConfigurationSection sysSection = configuration.GetRequiredSection("Sys");
    if (!sysSection.Exists()) throw new Exception("Missing section \"Sys\" in configuration!");

    var portAsString = sysSection.GetValue<string>("Port");

    options.Port = int.Parse(portAsString!);
})