There could be many reasons why you are experiencing the issue you mentioned. Unfortunately, I don't know anything about the experience you're going through. First, what Slingplayer software are you trying to connect on? What kinds of error messages are you getting? Are you able to connect and stream for a period of time before it disconnects? Does it happen on all devices you try connecting on, or just one?
I'm not saying you need to answer all these questions, but I'll need a little bit more information. Otherwise, I don't know exactly which issue I'm trying to troubleshoot.
Here, I'll drop this article related to picture quality and connection issues. If your problem is network-related, this may prove very useful to you.
Hope this helps!