If you only have one device, you probably have a very weak mesh, and your hub is probably having a hard time communicating with the device.
I would suggest getting a Z-Wave repeater. I use the Ring Alarm Extender Gen 2 (I have 6 around the house), which is rather inexpensive and also has an internal battery backup, and can send power fail events (switch from mains to battery) on power fail so that you can shut your hub down before it’s UPS dies (you do have your hub on a UPS, don’t you?).
You might find this document useful:
https://docs.hubitat.com/index.php?title=How_to_Build_a_Solid_Z-Wave_Mesh
I suggest you install Tony Fleisher’s (@tony.fleisher’s) excellent Hub Mesh Details app. It can give you insight to whether there are errors, signal strength, etc.
