Push Notifications on Chomebook
There are no push notifications on Chromebook, so the app should be launched all the time to receive incoming calls and messages.
In addition, please enable notifications for the Ringotel app in your Chromebook notification settings:
For Android apps, navigate to your device’s settings menu by clicking the system tray in the bottom right corner. Click the “gear” icon and on the left-hand side of the settings. Then you should see an “Apps” tab. Select “Manage Apps” and you should see the list of all your installed apps. Click on the Ringotel app, then simply toggle the notifications ON.