Hi,
Most probably your Shelly 1PM has left the HE Zigbee network shortly after joining it. The problem is not in the driver - the basic on/off switching should work also with the HE inbuilt Generic Zigbee Switch driver.
Try pairing the device again to your C-7 hub. If possible, bring it temporarily close to the hub. Then, reboot the hub. Start the pairing as soon as the HE web interface becomes responsive after the reboot.
You can use the HE inbuilt ‘Device’ driver for testing, clicking on the ‘Get Info’ button from the Commands tab should show the device fingerprint info in the live logs. When the ‘Get Info’ works on every click you can change the driver. Make sure the device continues to work after you power it off and then back on, Then you can move it to the final destination away from the hub, and test it again before you finally mount it inside the wall switch box.
Update: I hadn't had my morning coffee yet, so I missed that you are asking for Shelly 2PM (not 1 PM). 
Here is Joao's driver for Shelly 2PM Gen4 :
Update2: It may turn out that Shelly Gen4 devices will not work with Hubitat C-7 (and older) models, because of the older, non-Zigbee 3.0 compliant Zigbee stack :
At the end of this thread is the link to Joao's driver for Shelly 2PM, that works with the C-8 hubs. It may be a good idea to continue in that thread in order to avoid further confusion between 1PM and 2PM drivers.
