Your discourseEmbedUrl is still set to the URL of a topic on your Discourse site. It looks to me like that is the topic that you are wanting to create on Discourse, but you need to set it to the canonical URL of blog post that you are adding the code to.
Have a look at this topic for details: Embedding Discourse Comments via Javascript. Possibly what you are wanting to do is what is outlined in the (Alternate Configuration) Linking to existing topics section of that topic. In that case, you need to add a topicId parameter to the script. That parameter should be set to the id of the existing Discourse topic that you’d like to use.