First, confirm the Google API is configured in Magento.
Go to Google Analytics > Conversions > Ecommerce > Overview to see if Ecommerce is being tracked. 1. Confirm Google Analytics is installed and being tracked in general.
2. Go to the Admin configuration for Ecommerce to make sure it is enabled. Admin > Ecommerce Settings > Click to go to Ecommerce set-up screen
3. Make sure this functionality is enabled.