• Re-upload the feed
• Retransform the feed
• Confirm the feed is complete with no warnings
• Check if the correct feed filtering parameters were applied in the preview panel

The correct answer is: Check if the correct feed filtering parameters were applied in the preview panel

Explanation: The error is received when correct feed filtering parameters are not applied in the preview panel. When a user generates a dynamic preview, make sure the feed filtering parameters are correctly applied otherwise you will see the error “Can’t show a preview because you haven’t set a default creative or your applied filters don’t match any feed rows,”.