Thanks for using our answers forums! I'm sorry to hear you're having a bit of trouble with the SlingLinks.
There are a few factors that come into play when using the SlingLinks. First off, you'd want to check that the SlingLinks are plugged directly into the wall (no power strip/adapter/etc.) and check the lights on the SlingLinks. Here's an article from our support page which explains the basics,
Hope this helps!
The Sling Media Moderation Team