Open a different app entirely, or listen for Apple TV's own menu navigation sounds, before assuming your IPTV app is the one at fault here. If other apps have sound and only your IPTV app doesn't, the issue is specific to that one app's audio format or its internal decoder state, not the device as a whole. If the entire Apple TV is silent across every app you try, start with the physical remote's mute button and your TV or receiver's own volume level, since both of those sit completely outside the app you're troubleshooting and are worth ruling out first.

Apple TV lets you fix its audio output to one specific surround format instead of letting it auto-detect what each app is sending. If that fixed format doesn't match what your IPTV app's stream is actually sending, tvOS drops the audio entirely instead of converting it, so the picture plays normally alongside total silence. Go into Apple TV's audio settings and set the format to change automatically rather than locking it to one fixed surround format. This single setting resolves a large share of Apple TV sound complaints across many apps, not just IPTV specifically, so it's worth checking even if you're not sure it's the cause.

If sound plays fine right after you launch the app but then drops out after you've flipped through several channels in a row, the app's audio pipeline most likely didn't resync cleanly during one of those switches. This mirrors the same decoder-state issue that shows up on other streaming devices under similar conditions. Double-click the TV button on your remote to open the app switcher, swipe the app away to force-close it completely, and only then relaunch it, rather than just navigating back to the home screen and reopening it from there.

If both the picture and the app itself look completely normal but there's zero sound on any channel you try, and you have a receiver or soundbar connected over HDMI, the handshake between Apple TV and that receiver may have failed silently in the background. This can happen after the receiver reboots or updates its own firmware on its own schedule, leaving Apple TV sending a format the receiver simply won't play back. Unplug and replug the HDMI cable at the receiver's end, or restart the Apple TV itself, to force a completely fresh handshake attempt.

Rule out the provider before assuming the fault is entirely on your end: sound loss across every app and every device tied to the same account, not just Apple TV alone, points away from a local setting and toward something upstream on the provider's side instead. It's uncommon for audio specifically, but if it does happen, it's worth asking what uptime the service you're actually paying for guarantees in writing, rather than just taking it on faith. IP4KTV publishes 99.99% uptime, roughly 53 minutes of downtime a year, and backs its plans with a 7-day money-back window so testing your own setup doesn't carry a long commitment.