We are still investigating add issues. The latest update is as follows:
"We believe it's a caching issue with ads not being stored ready for you to watch. We recently changed our ad backend and updated it (this is a 3rd party piece of tech, nothing to do with the game or the game dev team) and it's one of the issues we're having with it. Video ads are downloaded and cached so they can be quickly pulled up when requested (when you hit the watch ad for Gauntlets, etc). But because no video ads are being cached, the button never activates so though the button in and of itself works, it's just not going to give you any ads because it thinks none are available.
We're certainty not throttling your ad limits and such deliberately but we're working with our external partners get that resolved. But since we don't do development on that particular piece of tech, we'll need to wait for them to sort it out for us. Hope that gives a bit more info"