Thanks for the reply, — I actually released the game (it's been moderately successful, too!), and turned the lack of ads into part of the marketing campaign for it. The first thing I did was to follow the shatter box tutorial but it did not work for me. Maybe I'm just obtuse, haha. But I think a lot of people are having similar issues implementing third party products and specially serving ads, so hopefully (and by the looks of it) it'll get addressed in future updates / Construct 3.
i have the same problem as you. all was work fine with the same parameters . but oups the error appear from nothing. and ads stop working. i think something wrong related to the cocoon plugins.