Embed HTML and JavaScript 

The ability to embed HTML and JavaScript  in New Sites is now available

To get started, select Embed from the Insert menu and choose Embed Code.

If inserting the code doesn't work for you try the following:

If it works in the incognito mode this indicates that you have an extension that is causing the problem. It may be an ad blocker or another extension. The Grammarly extension has often been the culprit.