Register page (XXX.Pages.Account)

using XXX.Pages.Models;

public class RegisterModel : PageModel
{
     private readonly IDataProtectionProvider _dataProtectionProvider;
     private readonly ILogger<RegisterModel> _logger;
     private readonly ApplicationDbContext _context;
     private readonly IReCaptchaService _reCaptchaService;
     private readonly HtmlEncoder _htmlEncoder;

    public RegisterModel(
         IDataProtectionProvider dataProtectionProvider,
         ILogger<RegisterModel> logger,
         ApplicationDbContext context,
         IReCaptchaService reCaptchaService,
         HtmlEncoder htmlEncoder)
    {
         _dataProtectionProvider = dataProtectionProvider;
         _logger = logger;
         _context = context;
         _reCaptchaService = reCaptchaService;
         _htmlEncoder = htmlEncoder;
    }

    // ......
}

ApplicationDbContext:

using XXX.Pages.Models;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;

namespace XXX.Pages.Models
{
    public class ApplicationDbContext : DbContext
    {
        private readonly IConfiguration _configuration;

        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options, IConfiguration configuration)
            : base(options)
        {
            _configuration = configuration;
        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                // Use the connection string from appsettings.json
                string connectionString = _configuration.GetConnectionString("ApplicationConnectionString");
                optionsBuilder.UseSqlServer(connectionString);
            }
        }

        // Correctly referencing the User model
        public DbSet<User> Users { get; set; }
    }
}

Error in Register page:

The type or namespace name 'ApplicationDbContext' could not be found

I tried adding the using XXX.Pages.Models to call in the function, but it is not working