Sandy's RING Doorbell will not chime on her mobile phone. She installed an app called ZEDGE and it suddenly stopped. Leo says you can check your RING doorbell health by going into the app itself. Then look in the settings and see if it's been changed by the ZEDGE app. That could have caused it. Make sure your notifications are enabled. Here's some other suggestions - https://support.ring.com/hc/en-us/articles/211676423-How-to-Troubleshoot-Ring-Notification-Issues-for-Android-Devices
Leo also recommends deleting ZEDGE and resetting your RING app.