Groupme App Notification Not Working S7

Groupme app is not notifying me when I am receiving messageson my S7. It does not display the message or make a notification sound, particularly when I am on the lock screen. When I am on the home screen it only pops up momentarily when receiving a message, but it does not make a notification sound. In essence, push notifications isn't working. I tried making sure that all the settings in both the app and the phone will allow notifications to appear, but I am still not receiving push notifications. Any idea how I can solve this?