If the keypad is not getting a good signal from the hub you may need a zigbee repeater. Try moving it closer to the hub to get it to connect.
Not sure what you are using, but suggest the following:
First install this DTH
Then follow info at this link
After it’s installed, you need an app to make it useable with ST and SHM. I shamelessly suggest my app SHM Delay Version 2