I'm suddenly having an issue with a single insteon on/off toggle switch located in my utility room in basement. The switch works fine manually to turn it on or off. When I try to turn it off from the ISY console that works fine, but then it won't turn back on from there or mobilinc app or alexa. I get an error messaging that the ISY can't communicate with that switch. I've tried removing the switch from the ISY and adding back in and that didn't fix the issue. I also replaced with another extra brand new toggle switch I have and it showed same behavior. This switch has worked for a year with no issues and now suddenly this has started. Any ideas on how I fix or what could be the problem? 

Would also like to add that occasionally(25%) the switch will turn on from ISY console. 75% of the time is doesn't turn on and gives me error message indicating ISY can't communicate with switch. however, I can always turn it off 100% of the time from the console. Very confused on why this is happening. Any help is appreciated. 

The first things that come to mind are lack of communication between legs of electrical system, or lots of noise or interference on circuit with PLM.  Have you confirmed phase coupling via dual-band device and instructions in manual?  Do you have other electronics on circuit with PLM, such as computer, UPS, modems, routers, etc....?