Currently, if you try to upload an image with a tall aspect ratio to the compose box for an Instagram Story post, the compose box will not allow you to schedule the post, or publish it to the Instagram Reminder Profile citing incorrect image aspect ratio.

If you save it as a Draft though, and publish it from your Drafts folder, it seems to work fine, which makes sense because it has the aspect ratio Stories always have.

It would be great if the image restrictions for Instagram Stories were correct.