Mixed Content Error - post now not visible

.

While editing a post on my blog in Chrome, I got the message about "mixed content error". The links within the blog will no longer access that page ("page does not exist") unless they are typed in manually.

How do I get the links to work correctly again? Within the post, all references to "https://" have been edited back to "http://"

Clicking on any of the shortcut links within the page, like the (***) or copying the link by right-clicking, and then entering it back into the address bar, the page is not found.

Any help would be most appreciated!!

All the other posts still work just fine within this blog, it is only this specific post.