If you see an message as shown below on the Dashboard this means that there is no activity such as 'Email', 'Phone' or 'Meeting' activity for the past month and hence the Dashboard Activity Timeline will be blank - hence the red message as shown in the example below:
As soon as you start to record any History activity for your contacts then this will populate the Dashboard with the recent activity and the activity timeline will then be displayed.
If you want to view past activity you can select the dropdown menu on the Activity Timeline as shown below to look back at activity for the past 6 months - if there is activity to display the activity timeline will then be displayed - as shown below:
