In order to send Shopify Transactional Messages through Listrak, you must upgrade your permissions to allow a different level of access to both Customers and Fulfillment for the Listrak integration.
The easiest way to ensure you have all of the appropriate permissions is to Upgrade the Shopify Public App to the latest version.
If you are still using the Listrak Shopify Private App integration, we also recommend upgrading to the Shopify Public App.
If you wish to continue to use the Listrak Shopify Private App, you will have to update your Shopify Private App Admin API permissions:
Navigate to Shopify Admin > Apps and click the Manage private apps link near the bottom of the page
Click on the Private app name for the Listrak Private App
Change the Customers Admin API Permissions to "Read and write"
Change the Fulfillment Admin API Permissions to "Read access"
Click Save to apply the changes to these permissions
Confirm the changes by clicking Edit private app