I am running same code on ASP.NET Core, the get request working well and it populate the view but when it comes to form submission it says bad request. I am not sure why it is happening. It is not totally hitting the OnPost Method in code behind.

Here is my Razor page:

@page
@using Northwind.EntityModels
@model Northwind.Web.Pages.SupplierModel
@addTagHelper *, MicroSoft.AspNetCore.Mvc.TagHelpers

<div class="row">
    <h1 class="display-2">Suppliers</h1>
    <table class="table">
        <thead class="thead-inverse">
            <tr>
                <th>Company Name</th>
                <th>Country</th>
                <th>Phone</th>
            </tr>
        </thead>
        <tbody>
            @if (Model.Suppliers is not null)
            {
                @foreach(Supplier s in Model.Suppliers)
                {
                    <tr>
                        <td>@s.CompanyName</td>
                        <td>@s.Country</td>
                        <td>@s.Phone</td>

                    </tr>
                }
            }
        </tbody>
    </table>
</div>
<div class="row">
    <p>Enter details for a new Supplier.</p>
    <form method="post" asp-page="/Supplier" novalidate>
        <div>
            <input asp-for="Supplier.CompanyName" placeholder="company name"/>
        </div>
        <div>
            <input asp-for="Supplier.Country" placeholder="country name" />
        </div>
        <div>
            <input asp-for="Supplier.Phone" placeholder="Phone name" />
        </div>
        <input type="submit"/>
    </form>
</div>
@{
}

And this is my code behind, any explanation will be welcome as I am learning it. I asked so much to chatgpt but not able to get an answer.

using Microsoft.AspNetCore.Mvc;// To use [BindProperty], IActionResult.
using Microsoft.AspNetCore.Mvc.RazorPages;
using Northwind.EntityModels;

namespace Northwind.Web.Pages
{
    public class SupplierModel : PageModel
    {
        private NorthwindContext _dbContext;
        public IEnumerable<Supplier>? Suppliers { get; set; }

        private readonly ILogger<SupplierModel> _logger;

        // add a property to store a single supplier
        [BindProperty]
        public Supplier? Supplier { get; set; }

        // OnPost that adds the supplier to the Suppliers table
        public IActionResult OnPost()
        {
            _logger.LogInformation("Onpost method excuted at {time}", DateTime.Now);

            // validation rule checking according to entity model 
            // like required, string length
            if (Supplier is not null && ModelState.IsValid)
            {
                // Log company name
                _logger.LogInformation("Valid Supplier data received: {companyName}", Supplier.CompanyName);
                WriteLine("is valid supplier");

                _dbContext.Suppliers.Add(Supplier);
                _dbContext.SaveChanges();

                return RedirectToPage("/Supplier");
            }
            else
            {
                // Log a warning 
                _logger.LogWarning("Invalid supplier data or ModelState is not valid"); 
                WriteLine("not valid supplier");

                // Return the original page
                return Page();
            }
        }

        public SupplierModel(NorthwindContext db, ILogger<SupplierModel> logger)
        {
            _dbContext = db;
            _logger = logger;
        }

        public void OnGet()
        {
            ViewData["Title"] = "Northwind B2B -Suppliers";
            Suppliers = _dbContext.Suppliers
                                  .OrderBy(c => c.Country)
                                  .ThenBy(c => c.CompanyName);
        }
    }
}

My folder strcutre: