Monoprice Z-Wave Plus Smart Plug Set-up Issues

This is all new to me (newbie) and I was hoping it was as simple as plug and play…which I thought it was supposed to be.

Yesterday I unwrapped my SmartThings Hub and went thru all the steps to get it up and running. Then it was time to add a device.

The only one I currently have is a Monoprice Z-Wave Plus Smart Plug and Repeater with 2 USB Ports - Product # 27481

Got it to add, renamed it, and made it a favorite. Tried to get it to switch on and off but it didn’t respond for the first 3-4 minutes.

Finally got it to switch on and then off. Tried again, no luck. Got it to work once more but that was it.

Got up this AM and it showed “device unavailable” It’s about 50’ from the hub but on the other side of a solid door. Opening the door has had no effect as the door was open last night while it was intermittent too.

I removed the device and added it back just as before. But now it still won’t talk and I have moved it 25’ away with line of sight. Even did a repair Z-Wave Network, but no change

I’ve also added an Echo Dot and an Ecobee Smart Si thermostat…all of which are working fine.

Any thoughts on the Monoprice Z-Wave Plus Smart Plug ? Thanks

How do you set it up out-of-the-box? Do you need a device handler?