Campaign Name Not Displayed for External Webpage Activity in Eloqua Insight

Summary:

An email was sent from a campaign in Eloqua, and the email contains a link to an external webpage.

However, when generating a report in Eloqua Insight by combining the Campaign Name from the Campaign Activity Metric and the Webpage URL from Webpage Activity, the Campaign Name field appears blank.

The Eloqua tracking script is embedded in the external webpage, and the "Add tracking for untracked external pages" option is enabled in the email asset.

The Campaign Name displays correctly for Eloqua landing pages. I would like to ask why it does not display for external pages.