“arecord: main:788: audio open error: Device or resource busy”

I can’t make work the Respeaker 4 mic array for the Raspberry.

I’m using the Raspberry pi 3+, with docker installed. The mic seems to work good when there’s no docker installed, but once I install docker, seems that the mic is “busy”.
After doing a “ps -A”, I don’t see any related mic service.

Any hints?

Thanks