The timeline should be seamlessly showing temperature data of the last 30 days. If your phone was off or out of Bluetooth range, then it will recover the missing data from the sensor's memory as soon as they are connected again.
If you see a gap or a grey block in your timeline, it means that phone and sensor were not connected long enough for the past data to load. After some time in proximity to the sensor, the timeline fills in missing data in the app.
>> If you haven't started receiving temperature data a couple of minutes after connecting your phone to the sensor again, please send us an email using the ‘Send Feedback’ option in the app’s side menu and we will get back to you as soon as possible.