I was in the air when I got a call and I declined it but returned to IF and the sound was not working. I checked the volume, the ringtone mute button, and the game setting and it was supposed to be on. I contacted tower and could hear that but not my aircraft noises. I know I could restart the app but it was during a flight which you cannot restart during.
I’m on a 7th gen iPad, All updates to iOS and IF app.