Thanks for using answers.slingbox.com! I apologize for the inconvenience of not being able to connect to your Slingbox from your iPhone 5. It seems as if your Slingbox may not be setup for TCP streaming.
There is not a way to test this from you end, so I would recommend contacting Sling Media Support and they can check this for you. If it is not setup for TCP streaming, there is an article on our support site that explains what you can do.
Here is the link:
Here is how you can contact us:
Hope this helps!
The Sling Moderation Team