I assume there's a few other cordcutters who have to deal with WatchESPN's stupid blackouts at least 2-3 times a season. Here's a 5 minute tutorial on how to tell ESPN you're actually located in a TV market where the game is not blacked out.
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For ACC Network games you can always watch in the ACC app regardless of blackouts. They don't make easy to find though. You have dig through the schedule of every ACC event.
What app are using? I couldn't find any live TV on the AppleTV ACC Digital Network app, it looked like just highlights.
The ACC app on iOS and Android. Its different than the ACC Digital Network app. For Android I was able to mirror it to my Fire TV. Not sure if you can do it with iOS to Apple TV. And there is always the old hook the laptop up to the TV trick.