When in the Sound Recorder, clicking the red circle does nothing.
The app needs permission to use your microphone:
If the issue continues, your microphone may be blocked by your IT Support. Please forward this article to them.
The corresponding setting in the Google Admin console is:
Devices > Chrome > Settings > Users & browsers > Audio input (microphone)
https://support.google.com/chrome/a/answer/2657289?hl=en#audio_capture_allowed&zippy=%2Caudio-input