Also, please note your service file is very different from what we recommend in the blog post.
You likely just need:
[Unit]
Description=FlowForge Device Agent
Wants=network.target
Documentation=https://flowforge.com/docs
[Service]
Type=simple
# Run as normal pi user - change to the user name you wish to run FlowForge Device as
User=root
Group=root
WorkingDirectory=/opt/flowforge-device
Environment="NODE_OPTIONS=--max_old_space_size=512"
ExecStart=/usr/bin/env flowforge-device-agent
# Use SIGINT to stop
KillSignal=SIGINT
# Auto restart on crash
Restart=on-failure
RestartSec=20
# Tag things in the log
SyslogIdentifier=FlowForgeDevice
#StandardOutput=syslog
[Install]
WantedBy=multi-user.target
root@ServidorTelemetria01:/etc/systemd/system# cat flowforge-device-agent.service
[Unit]
Description=FlowForge Device Agent
Wants=network.target
Documentation=https://flowforge.com/docs
[Service]
Type=simple
# Run as normal pi user - change to the user name you wish to run FlowForge Device as
User=root
Group=root
WorkingDirectory=/opt/flowforge-device
Environment="NODE_OPTIONS=--max_old_space_size=512"
ExecStart=/usr/bin/env flowforge-device-agent
# Use SIGINT to stop
KillSignal=SIGINT
# Auto restart on crash
Restart=on-failure
RestartSec=20
# Tag things in the log
SyslogIdentifier=FlowForgeDevice
#StandardOutput=syslog
[Install]
WantedBy=multi-user.target
root@ServidorTelemetria01:/etc/systemd/system#