1. Run the defender delegation wizard for the defender account.
2. Configure the Defender Security Server. Removed on old unused Domain Controller.
3. Restarted Services on the Defender Security Server application.
4. Defender Management Portal: The session may have timed out, cookies are disabled, or the website cache is corrupt. Cleared the cache and cookies, and restarted browser.
5. Confirmed no reports listed in the path: C:\Program Files\One Identity\Defender\Management Portal\WWW\Areas\Reports\ScheduledReports
6. Confirmed that Defender Users and Domain Admins group are are not nested in a large numbers of groups.
7. Defender Web Interface site in the IIS Manager to check if web page has been configured. Port 8080 and Authentication Pool. In the Defender Web Interface menu "Authentication" is set to Anonymous
8. Restarted the IIS Defender web page.