It’s recommended to use sudo ./edit-config python.d/hddtemp.conf rather than editing or copying configuration files manually. If you run this command, it should generate the default configuration for you, so you’d then just have to save it.
Can you see any other Python plugins running through the Netdata dashboard (you can check that under “Netdata Monitoring → python.d”
If you do a nc 127.0.0.1 7634, can you see your drive’s temperature?