We’ve confirmed that previewing real content is working. We’re sorry for the trouble!
Jan 24, 21:03 UTC
Previewing real content before adding them to your course is working normally again. We're continuing to monitor performance. We'll keep you posted with any other updates.
Jan 24, 20:14 UTC
You may be unable to preview real content before adding them to your course. You will see a blank page. As a workaround, select the course and preview it once you have created it. We are working on a fix, and we will update you as soon as possible. We are so sorry for the trouble.
Jan 24, 19:10 UTC