If you changed the battery in your product, or opened the metal back cover of the watch, you may have put it back on upside down. The metal part is part of the electronics of the product, if you put it upside down or you don't screw it enough, the sound signal will not work.Try to put it back in the right direction and tighten the screws well so that the contact is made inside. The sound signal works again.If the sound signal still does not work, contact our support team on this page.