Welcome to the Slingbox answer forums. This is a strange issue you are having. With the app there is very little trouble shooting. What I would suggest is to uninstall the app and reinstall it. We see this clears most if not all of the issue that you have with the Slingplayer. Being that you can connect on another device I do not feel it is the Slingbox that is the issue. Please let us know what happened after you refresh the app.
Sling Moderation Team