Check the physical mute switch on your iPhone. Some users report that sideloaded IPAs lose the “ringer volume” connection. Reinstall the app or toggle the “Change with Buttons” setting in Sounds & Haptics .
Since the official App Store requires iOS 16.0 or later for the current version, you must find the 11.49.9 IPA from legacy archives: Youtube 11.49.9 Ipa
If the app remains unstable, these methods are often more reliable for legacy hardware: Check the physical mute switch on your iPhone