Does not contain a static ‘main’ method suitable for an entry point

using CountryAPI.Models;

public class Program
{
    public static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
        builder.Services.AddControllers();
        builder.Services.AddEndpointsApiExplorer();
        builder.Services.AddSwaggerGen();
        builder.Services.AddSingleton<ICountryService, CountryService>(); // Singleton service

        var app = builder.Build();


// Configure the HTTP request pipeline.
        if (app.Environment.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseSwagger();
            app.UseSwaggerUI(c => { c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1"); });
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseAuthorization();
        app.MapControllers();
        app.Run();

    }
}

Program runs in Visual Studio but shows CSC 5001 error when using docker build command in terminal.

1. Tried changing the output type to exe
2. Made sure program was in compile mode
3. Added a main method
4. Restarted everything