React-App not showing only on port 80 on Server 2012 R2? - create-react-app

Question

I have a full stack site designed to run on port 80 with the Node backend using port 5000. This site runs without fail on a Windows 10 machine.
When I copy it to a domain server running on 2012 R2 I cannot get it to function on port 80, although port 90 shows with no problems.
IIS is turned off and netstat -aon shows that Node is the PID using port 80. I then tried building the page and serving it with NGINX and am getting the same results, except that NGINX is now the process using port 80.
Here is the code I believe to be relevant but am uncertain of what to do with it.
My .env file for react-app is simple:
PORT=80
When switching to port 90 it functions successfully.
If I attempt to run through NGINX (with which I am unfamiliar) using the following configuration:
worker_processes 1;
events {
worker_connections 1024;
}
http {
# include mime.types;
# default_type application/octet-stream;
# sendfile on;
# keepalive_timeout 65;
# gzip on;
server {
listen 80;
server_name localhost;
location / {
proxy_pass http://localhost:90;
root C:\intranet\New_Test\frontend\build;
index $uri $uri/ /index.html;
}
location /api {
proxy_pass http://localhost:5000;
}
}
}
I still get nothing.
I have also tried it without forwarding port 80 to port 90 with the same results.
Do I have an incorrect configuration somewhere? The netstat also says that SYSTEM is using port 80 for some reason but it is also using a number of other HTTP ports.
** Edit **
I have since updated my nginx.conf file to this:
worker_processes 1;
events {
worker_connections 1024;
}
http {
# include mime.types;
# default_type application/octet-stream;
# sendfile on;
# keepalive_timeout 65;
# gzip on;
include mime.types;
server {
listen 90;
server_name localhost;
root html;
index /index.html;
location / {
try_files $uri $uri/ /index.html;
}
location /api {
proxy_pass http://localhost:5000;
}
}
}
This is working fine to display the site in port 90 but for whatever reason port 80 in inaccessible to me on this machine.

Answer 1

Switched to a different model. Putting this answer to close the question. Went with nssm (https://alex.domenici.net/archive/deploying-a-node-js-application-on-windows-iis-using-a-reverse-proxy - step 5) and hosted the built React portion through IIS and using NSSM to run node as a service. Works well on local machine if I set my REACT_APP_HOST to localhost. Now experimenting with pathing so that the server can be reached from any client, not just a page on the localhost server.