HTML Block Doesn't Appear in Preview
Note: This article provides steps for code provided by third-party sources. Any troubleshooting with third-party applications should be handled by the application’s support team or your custom developer.
When you are using the Design tool, you may encounter that some of your HTML will not display within the preview feature. This is due to how our tool previews content.
As an example, some HTML code includes JavaScript embed elements that can only be displayed on a live page. It is best to go ahead and Publish your content that includes HTML for you to preview and ensure that it looks the way you want.