Thanks for using answers.slingbox.com! I'm sorry to hear you are unable to stay connected to your Slingbox PRO-HD. Though you are able to stream Netflix without an issue, the Slingbox does use a significant amount of bandwidth. The Slingbox uses Quite a bit more than Netflix uses.
I would recommend running a speedtest on your network to verify you have sufficient upload/download speed. If it is anything below the minimum bandwidth requirements, that is most likely why you are having this issue.
Also, how is the Slingbox connected to your wireless router? Ex: Hardwired via Ethernet, Sling Links, wireless bridge, etc..
Below is a link to an article that tells the minimum system requirements for the Slingbox PRO-HD:
Hope I was able to assist!
The Sling Moderation Team