Im new to Asp.net core 7 mvc.I created a custom identity and roles and i want to assign roles to users during registration. However the roles are not being assigned to the respective users as my ASPNetUserRole table is empty. Below is the code.The users are being saved to the system but they are not being assigned the roles.

        [HttpPost]
        public async Task<IActionResult> Register(RegisterVM model)
        {
            if (ModelState.IsValid)
            {
                ApplicationUser user = new()
                {
                    UserName = model.UserName,
                    FirstName = model.FirstName,
                    LastName = model.LastName,
                    Email = model.Email,
                    Form = model.Form,
                    BirthDate = model.BirthDate ?? DateTime.MinValue
                };

                var result = await userManager.CreateAsync(user, model.Password);

                if (result.Succeeded)
                {
                    // Assign the selected role to the user after creating the user
                    if (model.SelectedRoleId != null)
                    {
                        var role = await _roleManager.FindByIdAsync(model.SelectedRoleId);
                        if (role != null)
                        {
                            await userManager.AddToRoleAsync(user, role.Name);
                        }
                    }

                    await signInManager.SignInAsync(user, false);
                    return RedirectToAction("Index", "Home");
                }

                foreach (var error in result.Errors)
                {
                    ModelState.AddModelError("", error.Description);
                }
            }

            model.RoleList = await GetRoleSelectListAsync();
            return View(model);
        }

ASPNETUSERROLETABLE
ASPNETUser table

Any help or advice is appreciated