If the email is being received in an email client (not webmail), the most important thing you can do is get a copy of the email in its native format and attach it to the case. The saving of the email needs to be done by the person who received it. So having the email forward from the constituent to you and then saving is not sufficient. If the email is being received in a webmail client, get a screen shot of the entire message can be useful.

In the case of Outlook that would be done via:
  1. Find the email and open it in its own window.
  2. Go to File > Save As or to the Windows icon at the top right > Save As.
  3. Change the Save as type to Outlook Message Format (*.msg).
  4. Click the Save button.
Once you have the exact content, compare that content to content in Luminate Online. The email should match some content in Luminate Online exactly. If it does not match exactly, then it's coming from somewhere else in the product.