In ATracker setting->settings, there is an option to change the alarm sound; when you select one sound, it will also play. So you can use that to check whether the device is muted.
Also, in iPhone->notification center, by default, the sound is on for ATracker, but you can double-check whether it is allowed to show notifications with sound there.
Please check whether the device is muted or in "Do not disturb" mode.
Please sign in to leave a comment.