Why does my eBay app notification only sound when I open it?

[Gob Shite]

Why does my eBay app notification only sound when I open it?
It's pointless as it used to sound perfectly on all my other phones. Do you use the eBay app and du you get notifications even when the so is closed?

 

[B. Diddy]

Which phone? Go to the system settings and see if the app is Battery Optimized -- if so, then try turning off Battery Optimization for it and see if that helps.