I think the issue may be with the fact the the Contact “Sensor” (did you mean “Switch”?) is an IAS Zone Device and as such may need to be armed by an IAS CIE device before it can be used?
It is quite straightforward to create a “Binary Sensor” and use one of the Binary Inputs to report state of a simple binary signal (eg On/Off).
You’ll need to create a suitable “extension” if using Z2M. Fortunately that’s easy now 