AUTHENTICATION FAILED when starting service using systemctl

I am using GCP instance with Ubuntu 19.04 Minimal on board. I want to run my Node.JS app as a service, I found out that I need to use systemctl.

I created the following .conf file:

[Unit] Description=Node.js Web Parser  [Service] ExecStart=/home/user/img/server.js Restart=always User=nogroup Group=nogroup Environment=PATH=/usr/bin:/usr/local/bin Environment=NODE_ENV=production WorkingDirectory=/home/user/img  [Install] WantedBy=multi-user.target 

Then

sudo cp -i imgparser.service /etc/systemd/system 

And when I try to start it systemctl start imgparser, I get the following error:

==== AUTHENTICATING FOR org.freedesktop.systemd1.manage-units === Authentication is required to start 'img.service'. Authenticating as: Ubuntu (ubuntu) Password:  polkit-agent-helper-1: pam_authenticate failed: Authentication failure ==== AUTHENTICATION FAILED === Failed to start imgparser.service: Access denied See system logs and 'systemctl status imgparser.service' for details. 

I don’t really know the correct password on this system, though if I correctly set a new password it doesn’t seem to work anyway. Anything I do wrong?