If a marketing associate at Northern Trail Outfitters is unable to see a data extension in the Preview

and Test section when trying to perform a test send of an email in Content Builder, it could be

because the data extension has the "Is Testable" flag unchecked. In Salesforce Marketing Cloud, data

extensions can be configured with various properties, including the "Is Testable" flag, which

determines whether the data extension is available for use in test sends and previews.

If this flag is not enabled for a specific data extension, it will not appear as an option in the Preview

and Test section, preventing associates from selecting it for test sends. Enabling this flag on the data

extension's properties allows it to be used for testing and previewing email content.

Reference: Salesforce Marketing Cloud documentation on data extensions provides insights into the

properties and configurations of data extensions, including the "Is Testable" flag and its impact on the

availability of data extensions for test sends and previews.