Go to Server >> public_html >>assets>>audio>>delivery-notification.mp3
Your custom tone must be less than 5 Seconds (.mp3)
You should not change the file name which is present here.
![](https://i.imgur.com/SnGsZDc.png)
If you are planned to change the delivery-notification with your custom sound, then you need to replace it with your own custom sound with delivery-notification