Go to Reports Settings
From your HubSpot Dashboard, navigate to Reports > Reports Settings.
Make sure the domains you want to track are listed in the domains table
Scroll to the Domains table and confirm that the domains you want to limit visitor tracking to are listed in the table. You can add additional domains and subdomains using the plus button.
Once you've added your external domains, make sure you click Save at the bottom of the Domains section to save and implement your changes.