I was having the same issue and I realized it is because I upgraded my phone and I no longer had the Cha-ching notification sound available anymore. I have fixed my issue now using the steps below.
Quick solution if nothing else works. Here is a link to the instructions I used from this article to help me find the solution. (https://www.google.com/amp/s/www.digitaltrends.com/mobile/how-to-customize-a-samsung-phone-notificat...)
// Download the sound again//
1. Go to https://www.zedge.net/ringtone/7acc40c0-5de3-4ea4-aa15-7c88cd0f7d1c
2. Download the sound.
// Add Sound into your Notification folder in your phone so it can be available in the list of sounds to select from//
1. Go to "My Files" in your phone and in recent files, find the cha-ching sound you just downloaded. It should be on top as its the last thing you downloaded.
2. Select it and then "Move" it to Internal Storage/Notifications folder in your phone.
// Select this Cha-ching sound for your Etsy App Sold item notifications //
1. Go to "Settings" app in your phone.
2. Navigate to "Apps" and then search for the "Etsy Seller" app.
3. Once you click on it, click "Notifications" and make sure "Allow sound and vibration" is checked.
4. Then click "Notification Categories" at the bottom. From here, you can set what sounds you want for any action from the Etsy app.
5. Click "Sold Order" (make sure you allow notifications) and click "Sound". This will open up that notification folder that we put our cha-ching sound in earlier.
6. From here, you should see a list of all notification sounds you have on your phone. Your downloaded cha-ching sound should appear as an option in this list. Simply click it and you are all set!!
Hope this helps
