Hello, I'm trying to implement a dual mono setup as outlined in this guide: https://www.hifiberry.com/docs/software/dual-mono-setup/. I'm able to see both of the devices I've created in piCorePlayer, but I can only use one at a time. When I attempt to run a new instance of squeezelite specifying card2, I get this error:
Error: opening audio device: Device or resource busy
Any clues as to why I can use both devices?