/home/rutkowski.br/.nvm/versions/node/v6.11.5/bin/pm2 start /home/rutkowski.br/backend/config/pm2.prod.config.js

/home/rutkowski.br/.nvm/versions/node/v6.11.5/bin/pm2 startup

It will generate
sudo env PATH=$PATH:/home/rutkowski.br/.nvm/versions/node/v6.11.5/bin /home/rutkowski.br/.nvm/versions/node/v6.11.5/lib/node_modules/pm2/bin/pm2 startup systemd -u EU\rutkowski.br --hp /home/rutkowski.br

After entering this I get

Platform systemd
Template
[Unit]
Description=PM2 process manager
Documentation=https://pm2.keymetrics.io/
After=network.target

[Service]
Type=forking
User=EUrutkowski.br
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
Environment=PATH=/home/rutkowski.br/.nvm/versions/node/v6.11.5/bin:/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
Environment=PM2_HOME=/home/rutkowski.br/.pm2
PIDFile=/home/rutkowski.br/.pm2/pm2.pid

ExecStart=/home/rutkowski.br/.nvm/versions/node/v6.11.5/lib/node_modules/pm2/bin/pm2 resurrect
ExecReload=/home/rutkowski.br/.nvm/versions/node/v6.11.5/lib/node_modules/pm2/bin/pm2 reload all
ExecStop=/home/rutkowski.br/.nvm/versions/node/v6.11.5/lib/node_modules/pm2/bin/pm2 kill

[Install]
WantedBy=multi-user.target

Target path
/etc/systemd/system/pm2-EUrutkowski.br.service
Command list
[ 'chmod +x /etc/systemd/system/pm2-EUrutkowski.br.service',
  'systemctl enable pm2-EUrutkowski.br',
  'systemctl start pm2-EUrutkowski.br',
  'systemctl daemon-reload',
  'systemctl status pm2-EUrutkowski.br' ]
[PM2] Writing init configuration in /etc/systemd/system/pm2-EUrutkowski.br.service
[PM2] Making script booting at startup...
>>> Executing chmod +x /etc/systemd/system/pm2-EUrutkowski.br.service
[DONE]
>>> Executing systemctl enable pm2-EUrutkowski.br
[DONE]
>>> Executing systemctl start pm2-EUrutkowski.br
Job for pm2-EUrutkowski.br.service failed because the control process exited with error code. See "systemctl status pm2-EUrutkowski.br.service" and "journalctl -xe" for details.
[ERROR] Exit code : 1
[PM2][ERROR] systemctl start pm2-EUrutkowski.br failed, see error above.

systemctl status pm2-EUrutkowski.br.service

[ERROR] Exit code : 1
[PM2][ERROR] systemctl start pm2-EUrutkowski.br failed, see error above.
[EU\rutkowski.br@azl-fcps-011 ~]$ systemctl status pm2-EUrutkowski.br.service
● pm2-EUrutkowski.br.service - PM2 process manager
   Loaded: loaded (/etc/systemd/system/pm2-EUrutkowski.br.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since śro 2017-11-29 11:45:35 UTC; 45s ago
     Docs: https://pm2.keymetrics.io/
  Process: 10478 ExecStart=/home/rutkowski.br/.nvm/versions/node/v6.11.5/lib/node_modules/pm2/bin/pm2 resurrect (code=exited, status=217/USER)

And after manually entering
systemctl enable pm2-EUrutkowski.br

I get
=== AUTHENTICATING FOR org.freedesktop.systemd1.manage-unit-files ===
Authentication is required to manage system service or unit files.
Authenticating as: mustafa.m.2
Password: