I'm assuming that you're referring to the older 'Silver' Crestron app as opposed to the newer 'Teal' Crestron GO app??
Since the Silver app was deprecated (in a blaze of glory!) about this time last year, and knowing Apple, it may be that you are seeing the final throes of its full demise. Of course there could easily be localized issues with either the network or config...
I would strongly recommend that you update the client's devices to the GO app (separate phone and tablet versions) for more *long-term* reliability...
Also, don't forget to update the SMW device symbols - there is a Crestron GO symbol that is different than the Crestron App symbol...
