Why have my eCPMs dropped to absolute 0?

I released my app on thursday morning, the first day my ePCMs were high, and i earnt a little from the videos watched, but since that one day, even though my viewed videos are raising, I'm earning 0. And my ePCMs are at absolute 0! Meaning I'm giving out free ads? Earning nothing at all, maybe someone could shed some light on this? Thank you.

 

Responded in a private message, but repeating here for anyone else with the same question.

This occurs when the eCPM attempts to calculate the projected eCPM on a single completed view, which makes sense that you'd see a spike. The eCPM is the effective cost per thousand impressions. In this case it was estimated based on 1 successful out of 1 attempted, which skyrocketed the value. It dropped back to zero after additional data was collected, equalizing the value.

The estimated eCPM becomes more dependable as the data pool increases with continued user activity.