A sudden loss in connection with the Slingbox could mean a couple of different things. Typically, it means that there is an issue with either the network you are connecting to remotely, or with the network at the home location. Does this happen only in one location, or any place you are trying to connect?
Here's a helpful article to walk you through some troubleshooting steps.
If it happens again, I'd also recommend doing a speed test on your network. I normally use speedtest.net to run a reliable network speed diagnostic.
Hope this was helpful!
Sling Media Technical Support