After taking a look at your Sling Account, I was able to see that your Slingbox is streaming over TCP. However, it's using port 5206. This could be related to the connectivity issue you've described earlier. Try opening port 5201 within your router's firewall settings, afterwords factory reset and reconfigure the Slingbox. If all goes well, the Slingbox should default to port 5201, if it's unavailable, it'll cycle upwards one by one until it can find an available port. It's worth a shot.
Best of luck,
I have been using the embedded player on my chromebox for a few months now with no issues at all. Just yesterday it stopped connecting. I can connect fine from all other devices in my house. Wanted to see if anyone else had the same problem and if they found a workaround.