As an owner of the original Lenovo Smart Clock, I liked it so much that I figured I would also pick up its cheaper and more barebones brother, the Lenovo Smart Clock Essential. While it obviously lacks the full-fledged touchscreen display of its more expensive sibling, I liked the idea of having a secondary device for clock and temperature display that also doubled as a smart Google Assistant speaker. Unfortunately, during the Google Home setup process it didn't seem to play as nicely during the WiFi pairing process. It turns out that if you have a Ubiquiti UniFi wireless access point like I do (the UAP-AC-LITE in my case), you'll need to make a slight tweak in your UniFi Controller settings.
Under the Site tab, make sure to disable "Automatically Optimize Network and WiFi Performance" (many folks recommend disabling this anyway to prevent automatic overwriting of custom settings).
Next, go to Wireless Networks → select the network your clock is going to connect to → Edit → Advanced Options → 802.11 Rate and Beacon Controls → uncheck the box for 2G Data Rate Control.
Now try going through the Google Home setup process again, and the Smart Clock Essential should finally connect!