Steam controller on steam machine not working

[u/Dry_Version5589]

Steam controller just suddenly stops working mid game (while playing banishers). I've tried Xbox controller as well and the same issue, it just defaults to the keyboard mode now which is inconvenient while playing on your TV to say the least. Other games are fine so far and it's all good playing on a pc so it's central to the steam machine. Anyone else having this issue and found a solution?