Thank you for posting in the answers forum! I'm sorry to hear you are having trouble connecting remotely to your Slingbox via iPhone and iPad. The first thing I would do, is verify that you have sufficient bandwidth at the location you are trying to connect to the Slingbox from. On your mobile device, you can go to iTunes and install the speedtest.net application for free. You will want to verify that you have sufficient upload and download speed.
Below are the network speed requirements for SlingPlayer for iPad which is the same for SlingPlayer for iPhone:
Feel free to reply!
The Sling Moderation Team