That's most likely because the post is still in "Draft" status. (This can also happen if your post is in "Pending" or "Scheduled" status.)
To PUBLISH the post, and make it visible on your live blog, you'll need to go to the post editor and click the "Publish" button at the top right.
Other Possible Post Statuses That You May Use
There are most common post statuses.
Viewable by everyone.
Scheduled to be published in a future date.
Incomplete post viewable by anyone with proper user level. (draft)
Awaiting to be published.
Viewable only to site Administrators.
Posts in the Trash.