Have lost the audio on Apple tv
No audio on streaming platforms. Software up to date. Audio is fine on TV. Should I do a restart in settings?
iOS 12
Ok. Then your issue is different from Apple tv sound not working.
Is your Apple TV connected to your TV directly, or some other equipment in between? Do you use the TV built-in speakers, or other audio setup?
Does the Home Screen make its sounds? Navigation left-right-up-down, Menu (one level up), etc.
If you have issues with a particular misbehaving app, then you can force-close it in the App Switcher, similar to iOS. Double-tap the TV/Home button, then swipe horizontally to select an app, swipe up to close.
It is fine and safe to do a restart of the device, in Settings, e.g. for troubleshooting purposes.
If all possibilities are exhausted, then you can do a reset, to go back to factory settings, which will also erase any customization. If you have partial audio, then reset is probably not the recommended solution to this issue.