Honeywell Zwave Switch

I installed a Honeywell ZW4008 switch and connected it to my hub. The switch shows as a device in the app and correctly reports it’s status, on or off. However I am unable to control the switch, cannot turn it on or off from the app. I have tried changing the device type in the ide but get the same result regardless of the type I select. Any suggestions?I can add that the switch goes offline when left in the off position.

Exclude the switch and pair it again, also look for Ghost devices which can interfere with the mesh stability

I tried the suggestions but have the same result. When reinstalling the switch I did get a message saying the device was not using the highest level of security and suggested I exclude and reinstall. As I had just done this I ignored the suggestion. Using the IOS app I notice the device icon has the device name and under that _PO_CODE_S….