This feature is only available in the Pro version of Independent Analytics.
There are a few reasons why you could see missing sales in the analytics.
Track logged-in visitors
First, make sure that you are tracking logged-in visitors. Otherwise, the activity of your logged-in customers will go untracked, leading to unrecorded sales.

Check the order statuses
Independent Analytics only reports orders with certain statuses, including Processing, Refunded, and Completed. If your store has custom order statuses added by a plugin, those won’t be tracked by default.
You can choose which order statuses should be counted via the Analytics > Settings menu. You can update these at any time to change which orders are shown in the analytics.

Check your error log
If the solutions above don’t help, then there may be an error occurring during the checkout process. Please enable error logging on your site and then wait until another sale goes untracked. You can then check the debug log for a “Fatal” error that occurred at the same time as the sale.
The debug log will be located in the /wp-content/
folder.
If you need additional assistance, please reach out to us at support@independentwp.com, and we’ll be happy to help.