I have a ChannelMaster CM-7500TB1 connected to Slingbox TV SB500. They both TV display connect fine, but the remote control functions on the Android phone don't have an effect on the Channel Master. Can't access the recorded DVR shows or change live channels. What am I doing wrong? I cannot seem to download the latest Sling app version (16.2 Something instead of 18.6.) either. Your advice is much appreciated.