Two common causes: missing microphone permission or the device is out of storage.
Fix 1: mic permission
iOS Settings > ValueStream > Microphone. Must be enabled. If you originally denied the permission, iOS won't ask again - you have to enable it here manually.
Fix 2: device storage
iOS Settings > General > iPhone Storage. If you're below 500 MB free, the audio recording will fail silently. Free up space and retry.
Fix 3: reinstall
If mic and storage look fine, delete and reinstall the app. Voice note transcription runs on-device and can get into a bad state that a reinstall clears.