Not Getting Chime on iPhone...

I used to get a 'chime' alert on my iPhone when someone rang the doorbell. Now all I get is a notification and a little vibrate, which is easy to miss.: in fact, I missed a delivery / pickup yesterday... I've re-installed the app and set up the doorbell twice, but no luck. All Notifications are turned on for Ring in Settings. The doorbell chimes when I press the button, but my phone doesn't. Any Ideas?