For a particular user, the Clarity Overview page is blank. This happens only when going through the Modern UX. A channel is in place to display the Overview page. The Overview page loads well when accessing from the Classic UI.
Release : 16.1.2
The channel did not display the out of the box Overview page. It instead had a custom page configured. The user had added additional portlets that would take extra time to load, into this page. The page itself would load after about 7 minutes. It would be blank till then.