It's fixed it was not linked properly.

This is what comes up when I type that.

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

When I used the guide to point it to my domain it just gives me an error.

● nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2018-04-15 18:09:47 BST; 1min 18s ago
Docs: man:nginx(8)
Process: 5355 ExecStop=/sbin/start-stop-daemon --quiet --stop --retry QUIT/5 --pidfile /run/nginx.pid (code=exite
Process: 5018 ExecReload=/usr/sbin/nginx -g daemon on; master_process on; -s reload (code=exited, status=0/SUCCES
Process: 5293 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
Process: 5421 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
Main PID: 5296 (code=exited, status=0/SUCCESS)

Apr 15 18:09:47 35thid systemd[1]: Starting A high performance web server and a reverse proxy server...
Apr 15 18:09:47 35thid nginx[5421]: nginx: [emerg] invalid number of arguments in "root" directive in /etc/nginx/si
Apr 15 18:09:47 35thid nginx[5421]: nginx: configuration file /etc/nginx/nginx.conf test failed
Apr 15 18:09:47 35thid systemd[1]: nginx.service: Control process exited, code=exited status=1
Apr 15 18:09:47 35thid systemd[1]: Failed to start A high performance web server and a reverse proxy server.
Apr 15 18:09:47 35thid systemd[1]: nginx.service: Unit entered failed state.
Apr 15 18:09:47 35thid systemd[1]: nginx.service: Failed with result 'exit-code'.
lines 1-17/17 (END)
● nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2018-04-15 18:09:47 BST; 1min 18s ago
Docs: man:nginx(8)
Process: 5355 ExecStop=/sbin/start-stop-daemon --quiet --stop --retry QUIT/5 --pidfile /run/nginx.pid (code=exited, status=0
Process: 5018 ExecReload=/usr/sbin/nginx -g daemon on; master_process on; -s reload (code=exited, status=0/SUCCESS)
Process: 5293 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
Process: 5421 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
Main PID: 5296 (code=exited, status=0/SUCCESS)

Apr 15 18:09:47 35thid systemd[1]: Starting A high performance web server and a reverse proxy server...
Apr 15 18:09:47 35thid nginx[5421]: nginx: [emerg] invalid number of arguments in "root" directive in /etc/nginx/sites-enabled
Apr 15 18:09:47 35thid nginx[5421]: nginx: configuration file /etc/nginx/nginx.conf test failed
Apr 15 18:09:47 35thid systemd[1]: nginx.service: Control process exited, code=exited status=1
Apr 15 18:09:47 35thid systemd[1]: Failed to start A high performance web server and a reverse proxy server.
Apr 15 18:09:47 35thid systemd[1]: nginx.service: Unit entered failed state.
Apr 15 18:09:47 35thid systemd[1]: nginx.service: Failed with result 'exit-code'.

I am wondering how do I configure nodeBB to be under my domain I already have registered. I use DigitalOcean to configure the nodebb under ubuntu. I used this guide: https://docs.nodebb.org/installing/os/ubuntu/