Starting on July 8th, 2021, at approximately 9:00pm ET, serving failed for a majority of Widgets installs. This resulted in Widgets content not being displayed on the pages where they are embedded. Service was restored on July 9th at 10:00am ET.
A configuration change at the CDN layer resulted in a redirect loop between http and https requests for Widgets. Reverting this change resolved the issue.
We will be adding synthetic monitoring to our Widgets serving endpoints to allow early detection of problems going forward.