??????????????????????? – Dog Whistle Free Review

I tried this once on a couple of dogs and I hit tap to whistle and it showed that it was whistling but the dogs did nothing I tried far from them and close to them but nothing happened I don't think it works on all dogs please fix then again I didn't know the dogs so maybe they were deff I don't know but please make it work on all dogs thank you ?
Review by Shopkiner on Dog Whistle Free.