Android Question rewarded video ads not raising _Rewarded event

i successfully mediate to adcolony.. receive live ads but after watching full video and close it the _Rewarded sub is not raised ,

edit: using rewarded video test ads from admob raised the _Rewarded event

edit2: .. in Adcolony settings i change the zone type from Preroll/Interstitial to Value Exchange/V4VC and its working now