Statistics Monitoring Widgets are not showing any data from an Edge SWG device.  This can happen after failover of a Primary to Secondary Management Center as well.

The Reactivate Statistics Monitoring job configures devices with a URL to send required configuration and upload statistics to Management Center. The hostname and IP address in this URL is determined by Management Center

By following the steps in the following Technical Document, you can create and run a Job in the Management Center to re-establish the device statistics monitoring:

https://techdocs.broadcom.com/us/en/symantec-security-software/web-and-network-security/management-center/3-3/add_monitor_devices/reactivate_statistics_job.html