Clogged pipe somewhere?
Burned out pump?
blown controller switchgear?
internally severed electricity cable?
Could be any number of things. could be expensive to fix, could be as cheap as spending 10 dollars on some descale solution and working it through.
if you could tell us a bit more information, it might be helpful
else it could be a case of "well I didnt think I had to fill the tank with water".