HTTP Error 404 when trying to access endpoint of ASP.NET core Web API

I've created a new ASP.NET core Web API project. But when I run it in my development environment it is giving me "HTTP Error 404. This localhost page can't be found.". I tried debugging the application by placing several debug points in Program.cs and ServiceExtension.cs class, but the program control doesn't seem to enter the Controller classes and Service classes. My program.cs is as below:

var builder = WebApplication.CreateBuilder(args);

// Including the path for configuration file for the NLog configuration.
LogManager.LoadConfiguration(string.Concat(Directory.GetCurrentDirectory(), "/nlog.config"));

// Add services to the container.
builder.Services.ConfigureCors();
builder.Services.ConfigureIISIntegration();
builder.Services.ConfigureLoggerService();
builder.Services.ConfigureSqlContext(builder.Configuration);
builder.Services.ConfigureRepositoryManager();
builder.Services.ConfigureServiceManager(); 
builder.Services.AddControllers().AddApplicationPart(typeof(CompanyEmployees.Presentation.AssemblyReference).Assembly);


var app = builder.Build();
if(app.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}
else
{
    app.UseHsts();
}
// Configure the HTTP request pipeline.

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseForwardedHeaders(new ForwardedHeadersOptions { ForwardedHeaders = ForwardedHeaders.All });
app.UseCors("CorsPolicy");
app.UseAuthorization();

app.MapControllers();

app.Run();

The ServiceExtension.cs class is below:

namespace CompanyEmployees.Extensions
{
    public static class ServiceExtensions
    {
        public static void ConfigureCors(this IServiceCollection services) =>
        services.AddCors(options =>
        {
        options.AddPolicy("CorsPolicy", builder => builder.AllowAnyOrigin().AllowAnyMethod().AllowAnyHeader());
        });

        public static void ConfigureIISIntegration(this IServiceCollection services) =>
            services.Configure<IISOptions>(options =>
            {
                //We are not adding any options becasue we are configuring for default ones
            });

        public static void ConfigureLoggerService(this IServiceCollection services) => services.AddSingleton<ILoggerManager, LoggerManager>();

        public static void ConfigureRepositoryManager(this IServiceCollection services) => services.AddScoped<IRepositoryManager, RepositoryManager>();

        public static void ConfigureServiceManager(this IServiceCollection services) => services.AddScoped<IServiceManager, ServiceManager>();

        public static void ConfigureSqlContext(this IServiceCollection services, IConfiguration configuration) => services.AddDbContext<RepositoryContext>(opts => opts.UseSqlServer(configuration.GetConnectionString("sqlconnection")));
    } 
}

The only controller class is as below:

namespace CompanyEmployees.Presentation.Controllers
{
    [Route("api/companies")]
    [ApiController]
    public class CompaniesController : ControllerBase
    {
        private readonly IServiceManager _serviceManager;

        public CompaniesController(IServiceManager serviceManager)
        {
            _serviceManager = serviceManager;
        }

        [HttpGet]
        public IActionResult GetCompanies()
        {
            try
            {
                var companies = _serviceManager.CompanyService.GetAllCompanies(trackChanges: false);
                return Ok(companies);
            }
            catch
            {
                return StatusCode(500, "Internal Server Error");
            }
        }

    }
}

Does anyone know what is going wrong here? or how can I effectively debug the solution?