Earlier today we migrated our marketing site (https://usabilityhub.com) to a new platform. Our CDN has historically been configured to fetch assets from usabilityhub.com. Our application's domain (app.usabilityhub.com) ran into issues as the assets it needed to run were no longer present on usabilityhub.com due to the move of the marketing site. As a result, JS and CSS was failing to load.
This effectively caused an outage of the product, which has now been resolved by reconfiguring our CDN to fetch assets from app.usabilityhub.com. We're uncertain how long we were affected for as the CDN's cache masked the issue for several hours after moving usabilityhub.com. It's likely this issue was affecting the site for about the last 30 minutes.