Aspnet Core Action request fails but everything works

Question

Why does the request fail even if everything works correctly?

public async Task<IActionResult> DeleteUser(String Cod)
{
   var User = await _context.AwsmAppusers.AsNoTracking().SingleOrDefaultAsync(m => m.Username == Cod);
   if (User == null)
   {
      return RedirectToAction("Index");
   }

   try
   {
      _context.AwsmAppusers.Remove(User);
      await _context.SaveChangesAsync();

   }
   catch (Exception e)
   {
      _logger.LogError("Si è verificato un errore nell'eliminazione dell'utente: " + e.Message);                
      return null;/*RedirectToAction("Delete", new { id = id, saveChangesError = true });*/
   }

   return RedirectToAction("UsersPage");
}

Why is the red marker displayed?

Answer 1

Hi @CriMig8 try to attach your User

      _context.AwsmAppusers.Attach(User);
      _context.Remove(User);
      _context.SaveChanges();