Smart device volume settings might be inappropriately set. Check the following settings in your device.
Allow Dario to use the microphone
Go to Settings
Tap Privacy
Then Microphone
Switch on Dario
Set Mono Audio
Go to Settings
Tap General
Then Accessibility
Switch off Mono Audio
Adjust Audio Balance
Go to Settings
Tap General
Then Accessibility
Set audio balance between L & R
Adjust Music Volume
Go to Settings
Tap Music
Then Volume Limit
Set Volume to maximum, and switch off EU volume
Adjust Ringer and alerts Volume
Go to Settings
Tap Sounds
Set ringer and alerts volume to maximum