I have the same issue. No picture or sound and crashes with "cannot connect" error message.
I contacted Samsung support and they told me that it is the Slingbox app that needs to be updated or patched to work with the NOTE4. That's it.
It is definitely not Android Lollipop version ....because the Slingbox app is working on a SamsungS5 and a Nexus7 tablet just fine under lollipop.
I would hope that the Slingbox folks can jump on this for a quick fix as Note4 is one of the most popular phones out there today and many customers who paid for the app will be shut out from using it.