You can build a report that shows units that haven’t connected within a time period, for example, units that haven't connected within the last 1 day.
Go to the Reports Manager and add a Units Report
Name the report, for example, “Units no connection last 1 day”
Double-click the report in the list
Set the criteria for the report:
Type: 1 DAY AGO
Run the report and see the results show units that haven’t connected in over 1 day ago
Make the report public if you want others to see the report
Save the report
Note: You can schedule this report to run by clicking the Schedule button.