How I solved it:
I installed the npm module localtunnel which allows me to tunnel my localhost to network without ssh. The new service looks like this:
ExecStart=lt --port 8003 --subdomain server-login
First, you should place your unit file in /etc/systemd/system/server-tunnels.service, not /lib/systemd/system/server-tunnels.service. The directory under /etc is intended for the local administrator while the directory under /lib is intended for the distribution.
The reason why the command doesn't work it that it doesn't know how to log in. Commands started ...
If you have dnsmasq installed you can verify with:
sudo netstat -laputeno|grep 67
If it is the case:
sudo systemctl disable dnsmasq
sudo systemctl stop dnsmasq
sudo systemctl start isc-dhcp-server