I took a look at your account, and noticed that your Slingbox is not using the current firmware. You will need to make sure that it is running an up-to-date firmware to ensure the Slingbox will work properly.
Check out this article first, you should be able to update the firmware of the Slingbox by going to setup.slingbox.com:
If there is not an option to do so, you may need to reset the unit back to default settings. Below will explain how to do this:
Sling Media Moderation Team