See also: Order attribution in Ometria
There are several possible reasons for this:
UTM tracking parameters are not being populated across your website
UTM tags are Google Analytics (GA) tags added to links in the email. When a user clicks on a link, GA can identify that user as coming from a particular traffic source channel (Email) from a specific campaign (Ometria_Newsletter X).
If the UTM tags are not populated throughout the users journey on the website (e.g. tracking parameters are stripped off while reloading or navigating to another page) certain GA attribution models no longer attribute any transaction to that email.
As Ometria doesn’t use universal tracking parameters (UTMs) for tracking, Ometria will continue to track it.
Orders made through Paypal or third parties are not tracked by Google Analytics
If the payment page on your website redirects to Paypal or a third party payment page where the link tracking parameters are stripped off, then GA will not be able to track that transaction.
Ometria will continue to track that order as Ometria doesn’t use UTM parameters to track campaign revenue.
Google Analytics does not report on revenue made in Amazon or eBay stores or other offline channels
Ometria can report on these stores so a discrepancy in revenue should be expected between Google Analytics and Ometria in these cases.