Meteor client cannot access to compiled production files

I'm trying to deploy my meteor server on my debian server. I'm using nginx and forever to run the bundled meteor app. (I followed the following tutorial : https://medium.com/startup-founder-panel/deploying-a-meteor-app-with-nginx-from-scratch-1332b32e99a5)

It's working for the server part (I'm connecting a react-native app on it and it works fine), but it doesn't work for the React web client part:

It says that it cannot load the js and css files, like if there where not accessible from the client, although they are actually there in the bundled folders in my linux server.

Here what's the error looks like:

GET http://example.com/ea63eb5bb7607b3ce74dca13734da44296043bb9.css?meteor_css_resource=true 404 (Not Found) GET http://example.com/051b222361019ff9f7996039dc35fb4902c12405.js?meteor_js_resource=true 404 (Not Found)

Here's what the index.html is containing: enter image description here

Here is the script is use to build/clean meteor:

meteor npm install
npm prune --production

rm -rf ~/bundle #Remove the previous bundle
rm -rf ~/portal

meteor --allow-superuser build --directory ~

cd ~/bundle/programs/server #Enter the bundle
npm install

mv ~/bundle ~/portal

mkdir ~/logs

# Use forever to start the Node server
export PORT=8080
export MONGO_URL='mongodb+srv://user:password@url'
export ROOT_URL='http://example.com'
export METEOR_SETTINGS='{ <fiew settings> }'
#export MAIL_URL='smtp://user:password@mailhost:port/'
cd ~/portal
forever stop main.js
forever start -a -l ~/logs/forever.log -o ~/logs/portal.out -e ~/logs/portal.err main.js

And here is my nginx config for the meteor app:

map $http_upgrade $connection_upgrade {
        default upgrade;
        ''      close;
}
#HTTP
server {
        listen 80 default_server;
        listen [::]:80 default_server ipv6only=on;

        location = /favicon.ico {
                root /root/portal/programs/web.browser/app;
                access_log off;
        }

        location ~* "^/[a-z0-9]{40}\.(css|js).*$" {
                gzip_static on;
                root /root/portal/programs/web.brower;
                access_log off;
        }

        location ~"^/packages" {
                root /root/portal/programs/web.browser;
                access_log off;
        }

        # pass requests to Meteor
        location / {
                proxy_pass http://127.0.0.1:8080;
                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade; #for websockets
                proxy_set_header Connection $connection_upgrade;
                proxy_set_header X-Forwarded-For $remote_addr;
                proxy_set_header Host $host;
        }
}

I know I'm missing something so the client can see the two css and js files but I can't find what anywhere after a day of trying.

Thanks a lot to the one that will unlock me!