The most common reasons:
The app embed is off — ECM Sales Popup must be switched on and saved in your published theme. If you changed your theme, turn it on in the new one too.
The pop-up is Disabled — new pop-ups are saved as Disabled until you enable them.
You've already seen or closed it — the app remembers this in your browser. Once you close or decline a pop-up, other pop-ups don't show either, and after a discount is applied no other pop-ups show for 14 days. Test in a private (incognito) window.
Two pop-ups compete — only the newest enabled pop-up with the same trigger shows on a page.
It's an exit-intent pop-up on a phone — exit intent works only with a mouse.
Growth's monthly views are used up — pop-ups pause until the reset or an upgrade (see How does billing work).
Checked all of these and still nothing? Chat with us and we'll look at your store.