how to get a repeating custom sound for new email until opened or deleted

[shlorp]

Missed Notification Reminder works except that it will not work on the smartphone (LG-K7) unless my computer (Win 10) is on. I have not been able to correct that unwanted aspect of synchronization.

Is there some app that works better for this or is there some way to be free of the computer having to be on?

 

[B. Diddy]

Welcome to Android Central! Is that Missed Notification Reminder an option in Settings>Accessibility, or is it a separate app?