Momentum only accepts calories from workouts that have been initiated on a wearable device i.e. starting an outdoor run on your watch. They also don’t accept any workouts entered manually. The calories also need to be burnt in a single workout session and not aggregated over the day like with steps. So when you are going to exercise, trigger a workout on your wearable device and make sure you get over 300 calories for the workout without pausing between workouts.