I have AVS running on my iMac and my ATV4 in the living room. Whenever I go to watch something, i get the message "Playback failed for Black Sails.mkv The operation could not be completed". Then I click continue, pick the same file again to watch and then it will play.
Not sure why it started doing this, but just wanted to let the dev know. Otherwise, I LOVE this app and software.