What this sounds like is the Internet Viewing for TCP (Transmission Control Protocol) streaming through the home router has failed.
I recommend to port forward the Slingbox through the home router. This step has to be done at the location of the Slingbox.
If you do not know how to do this, contact Sling Media Technical Support at 1-877-GO-SLING to see if they can help you out.
Help this helps!!!
Sling Media Moderation Team