How to get IMEI in API 11 Using Xamarin Form

I am using this code...

 public string GetIdentifier()
        {
            TelephonyManager manager = (TelephonyManager)Forms.Context.GetSystemService(Android.Content.Context.TelephonyService);

            return manager.Imei;
           
        }

var deviceInfo = Xamarin.Forms.DependencyService.Get();
             var number = deviceInfo.GetIdentifier();
            lblIMEI.Text = number.Trim();

but i  am getting error

Java.Lang.SecurityException: 'getImeiForSlot: The user 10308 does not meet the requirements to access device identifiers.'