Why is the fountain not running water anymore?

What could be occurring is potentially one of the following issues, either air could be lodged inside of the pump or the impeller was reassembled incorrectly. 

If the pump was removed and reassembled with air trapped inside, it might not be able to circulate water properly. Try submerging the pump fully in water for 5-10 minutes and turning it on to release air bubbles.

For the impeller, if parts weren’t reconnected correctly after cleaning, the water flow might be blocked, or the pump may not be seated properly. Please ensure that all components of the pump and stator are correctly aligned.