Product Family: Act!
Product: Act! emarketing
Version: v16.1 and later
Cause: This will occur if there is no data available to see at the time of viewing the report.
When a contact has opened the email you will see the Report information appear.
There are more details available on Reports in the article below:
How do I view and interpret my Act! emarketing reports?
Note: If the contact is viewing the email in an application, such as Microsoft Outlook, and have not downloaded images an open will not be logged in the Report