Instagram sound not working

The same thing happened to me. But I just plugged in my headphones and the audio started working. And after I unplugged them the audio was working as normal. Hope this helps :)

I know you said you had sound on other apps, so this will likely not be your best answer. For anyone else who doesn't have sound, make sure you check that you don't still have bluetooth headphones connected that aren't in/on your ears. It's an easy thing to do, I know! 😉