Get this error Raspi3 With Matrix Voice

sorry my English is not good, I get this error

Hardware is Raspy 4 and MatrixVoice and I have it set up according to this guide,

https://docs.snips.ai/articles/raspberrypi/matrix#the-matrix-boards

at the point where I should test

“amixer set PCM 100% && arecord recording.wav -f S16_LE -r 16000 -d 5 && aplay recording.wav”

I get this message

pi@raspberrypi:~ $ sudo amixer set PCM 100% && arecord recording.wav -f S16_LE -r 16000 -d 5
&& aplay recording.wav
Simple mixer control ‘PCM’,0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback 400 [100%] [4.00dB] [on]
arecord: main:788: audio open error: No such file or directory

what can I do?

Raspberry 4 is running Raspbian Buster and raspbian Buster is not yet compatible with Snips as far as I know, or they published the sources last week?