I have the same problem with the Chromecast Audio pausing every hour or so. Obviously, I update and reset all software and systems. Then I have tried an ethernet hook up directly from the router and set the priority of that connection. But no improvement. According to these posts, this problem has been around for a while. Is Spotify working on this?
We are aware of this issue and are currently investigating it. Feel free to contribute in this topic where we gather information from affected users and keep everybody up-to-date. We'll get this sorted as soon as possible.
Sorry for the inconvenience. Let us know if you have further questions.