You have created a report using API Call/Request for Symantec Endpoint Security (SES) Agent version SEP 16.
The API response does not have the "last_connected_time" field in it.
The same API call returns this value for SES 14.3.x client.
SEP 16
The "last_connected_time" attribute used for SEP 14 is stored in "last_updated" field for SEP 16 agents.
So, if there is a script/query used to get this data, it needs to be modified as: If products.version is not started from "14." get last_connected_date from "last_updated"
Reference API docs:
SEP 16: last_updated
SES: last_connected_time