I had this problem today when I had to turn off my router. When I rebooted that, got the hourglass. Realised I had turned off everything when I turned off the router, ie the Control4 box as well. So I did this:
turned off router
turned off Control 4 box
turned on router and waited until I could see it was working by checking on phone and doing a speed test
turned on Control4 box
took batteries out of remote and put back in
This seemed to work. Hope this helps someone else!