I got this problem. This even work when using start/stop but not on enable. What can be wrong?
pi@raspberrypi:/etc/systemd/system $ service gserv enable
gserv: unrecognized service
pi@raspberrypi:/etc/systemd/system $ service gserv status
Warning: The unit file, source configuration file or drop-ins of gserv.service c
● gserv.service - Gunicorn Flask
Loaded: loaded (/etc/systemd/system/gserv.service; enabled; vendor preset: en
Active: failed (Result: exit-code) since Sat 2020-10-24 23:50:18 EEST;