Press Vibrate Now Test. Ditto should vibrate 3 times.
Is the clip installed properly? See video here.
Is the battery installed properly - positive (+) side DOWN. Is the battery power OK?
In the Wear Ditto App Menu, tap "Battery". Change the battery to a fresh CR1632 when you get a notification to do so. See video here.
Is Ditto paired properly to Bluetooth through the Wear Ditto app?
Call or text your smartphone. Ditto should vibrate in either case, even if the app is not running. See video here.
Are the desired notifications turned ON in the app?
Is the iPhone’s Do Not Disturb (DND) turned ON? Ditto will follow those times.
Is Ditto’s DND turned ON?
Do you have Favorite ON, but messages are coming from non-favorites?