Hello @KBrennan ,
When you preview your email, or send a test send, the contact detail (including subject line personalization and greeting tags) displays the personal information you provided for your own account to give you an idea of what your contacts will see. If the information isn't available to pull into your preview, or if you're using custom fields, the fallback text displays instead.
If you want your test individuals to see the personalization elements, you'll need to send it as a regular email directly to them (i.e. adding them to a list on their own, then sending the "test" email to that list).
... View more