Lit-html not found when using polymer build - nginx

Question

I have a fairly basic lit-html app that works locally when it's not build.
However when I build it using polymer build using the following config:
{
"entrypoint": "index.html",
"shell": "src/school-home.js",
"sources": [
"src/**.js",
"package.json"
],
"extraDependencies": [
"node_modules/#webcomponents/webcomponentsjs/bundles/**"
],
"builds": [
{"preset": "es6-bundled"}
]
}
This results in a successful build but for some reason I keep getting an error:
I just don't get why it doesn't work. This like the basics of the basics yet it doesn't get found?
Aside: I use nginx for windows since I want to test E2E with my developed APIs.
An additional issue is that I keep getting CORS error for my API calls even though they are on the exact same location?!!
Please help.
Edit:
My NGINX config:
worker_processes 1;
events {
worker_connections 1024;
}
http {
include cors-settings.conf;
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
server {
listen 8000;
server_name localhost;
location /school {
root /html/ing-school;
try_files $uri $uri/ $uri.html /index.html;
}
location ~ ^/(api|login|logout) {
proxy_pass http://localhost:8080;
proxy_set_header Connection "";
if ($request_method = 'OPTIONS') {
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Max-Age' 1728000;
add_header 'Content-Type' 'text/plain; charset=utf-8';
add_header 'Content-Length' 0;
return 204;
}
if ($request_method = 'POST') {
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
}
if ($request_method = 'GET') {
add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested- With,If-Modified-Since,Cache-Control,Content-Type,Range';
add_header 'Access-Control-Expose-Headers' 'Content-Length,Content- Range';
}
}
location /ws {
proxy_pass http://127.0.0.1:8080;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
}
error_page 404 /404.html;
location = /40x.html {
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
}
}
}