Different day, different problem.
I'm getting the same now on both android and iOS.
The culprit is Fyber. Don't believe I've seen this provider in quite a while.
We'll never know what the advert is because it won't load. It just throws out the error message. However in iOS it leaves me the escape cross in the top right of screen. Hit this and it ask if I want to forfeit my reward. This is where I'm getting Fyber from.
Will try and get a screen shot.