When are notifications not read out by Activity Reader?

Notification type	Scenarios
Incoming calls	When your phone is not in Vibrate mode while you're using a wired headset.
Messages and calendar events	When messages are from phone numbers that are not stored in your contacts. When a call is in progress. When there's an incoming text message, your phone will only play a notification sound and will not read out the message content. When any of these settings are enabled: Do not disturb mode TalkBack Disable SMS and Calendar read-out when the display is on option in the Activity Reader settings