Sound Notifications Not Working - iPhone

Let's first try checking the notification settings in the app to ensure everything is set correctly:

Follow these steps:
Main Menu > Settings > Audio and Notifications
- Make sure that In-App message alerts are turned on to vibrate and play sounds.
- If you are a Voxer Pro member, you can adjust Extreme Notification settings from this page as well.

We also recommend double checking the push notification settings on your iOS device to ensure the notification is turned on for the app.

Try these steps:
Go to Settings > Notifications, select the app, and make sure that Notifications are turned on.
If you have notifications turned on for Voxer but you're not receiving alerts, the alert style might be set to None. Go to Settings > Notifications and check that your Alert Style is set to Banners or Alerts.

Make sure that you’re signed in to your Apple ID. Go to Settings > iTunes & App Stores and enter your Apple ID and password. Make sure that Do Not Disturb is turned off. Go to Settings > Do Not Disturb and tap Manual if it's turned on.

If you’ve recently re-installed the app or restored from a backup, open the app to start getting notifications.

If you are not hearing a chirp when you send a message, you can adjust your settings in the Main Menu > Settings > Audio and Notifications > scroll down to Push to Talk button section > adjust the chirp volume to your desired level. 

If you performed all of these steps and your problem persists, we recommend ensuring that you've upgraded to the most recent version of the OS and Voxer available for your device. Here is the link to some general troubleshooting tips and best practices. https://support.voxer.com/hc/en-us/articles/204330023-Troubleshooting-Tips