The code in your final screenshot is showing the URL of a Discourse topic as the value of the discourseEmbedUrl. The discourseEmbedUrl should be set to the canonical URL of the page you are adding that code snippet to. For example, if the URL of the post you are adding the snippet to was https://example.com/blog/my-new-blog-post, that is the value that you would use for the discourseEmbedUrl.
It also looks like there may be a formatting issue in your code snippet. Notice the large amount of space between the opening ' and the beginning of the URL.