Hi all,
just the day after getting everything fine: https://forum.nginx.org/read.php?2,286991,287001#msg-287001, during installation of another software in the PC I got problems with grub system in Ubuntu 18.04.4 Desktop, which I resolved copying, from an installation iso image, the /bin/bash folder: https://askubuntu.com/questions/1210267/missing-operating-system-error-unknown-filesystem-grub-rescue

But to my surprise, now I'm not able to see my webpage anymore, even if, apparently, everything seems ok.
"
This site can’t be reached https://ggc.world/ is unreachable.
ERR_ADDRESS_UNREACHABLE " :

https://drive.google.com/open?id=1NYLyXP5zpFN5_9TkWspY6FymaMauKUGv

And this is remarked with the digicert's and check-your-website-server's checks:
- https://drive.google.com/open?id=1EeOYkWzHXaMmOJKBnBbPYS-F9fcyPFXM
- https://drive.google.com/open?id=1DzuQlm6wkWvH7_-yfRowM45sAm2FKMWa


But apparently seems everything ok:


(base) marco@pc01:~/webMatters/vueMatters/testproject$ npm run serve

> testproject@0.1.0 serve /home/marco/webMatters/vueMatters/testproject
> vue-cli-service serve

INFO Starting development server...
98% after emitting CopyPlugin

DONE Compiled successfully in 906ms 9:36:31 AM


App running at:
- Local: http://localhost:8080
- Network: http://ggc.world/

Note that the development build is not optimized.
To create a production build, run npm run build.



(base) marco@pc01:~$ sudo nano /etc/nginx/nginx.conf
[sudo] password for marco:


user www-data;
worker_processes auto;
pid /run/nginx.pid;

events {
worker_connections 768;
# multi_accept on;
}

http {

# Basic Settings

sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
# server_tokens off;

server_names_hash_bucket_size 64;
# server_name_in_redirect off;

include /etc/nginx/mime.types;
default_type application/octet-stream;

# SSL Settings

ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3;
ssl_prefer_server_ciphers on;
# Logging Settings
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
gzip on;

include /etc/nginx/conf.d/*.conf;
}


sudo nano /etc/nginx/conf.d/default.conf :

server {
listen 443 ssl http2 default_server;
server_name ggc.world;

ssl_certificate /etc/letsencrypt/live/ggc.world/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/ggc.world/privkey.pem; # managed by Certbot

ssl_trusted_certificate /etc/letsencrypt/live/ggc.world/chain.pem;

ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot



ssl_session_timeout 5m;
#ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3;
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers EECDH+CHACHA20:EECDH+CHACHA20-draft:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;
ssl_prefer_server_ciphers on;
ssl_session_cache shared:SSL:50m;
#ssl_stapling on;
#ssl_stapling_verify on;

access_log /var/log/nginx/ggcworld-access.log combined;

add_header Strict-Transport-Security "max-age=31536000";
location = /favicon.ico { access_log off; log_not_found off; }

location / {
proxy_pass http://127.0.0.1:8080;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
#proxy_set_header Host $host;
}
}

server {
listen 80 default_server;
listen [::]:80 default_server;
error_page 497 https://$host:$server_port$request_uri;
server_name www.ggc.world;
return 301 https://$server_name$request_uri;

access_log /var/log/nginx/ggcworld-access.log combined;

add_header Strict-Transport-Security "max-age=31536000";
location = /favicon.ico { access_log off; log_not_found off; }

location / {
proxy_pass http://127.0.0.1:8080;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
#proxy_set_header Host $host;
}
}

upstream websocket {
ip_hash;
server localhost:3000;
}

server {
listen 81;
server_name ggc.world www.ggc.world;

#location / {
location ~ ^/(websocket|websocket\/socket-io) {
proxy_pass http://127.0.0.1:4201;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header X-Forwared-For $remote_addr;
proxy_set_header Host $host;

proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
}
}

(base) marco@pc01:~$ sudo systemctl status nginx
● nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2020-02-17 07:52:51 CET; 1h 58min ago
Docs: man:nginx(8)
Process: 8830 ExecReload=/usr/sbin/nginx -g daemon on; master_process on; -s reload (code=exited, status=0/SUCCESS)
Process: 1090 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
Process: 1067 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
Main PID: 1092 (nginx)
Tasks: 9 (limit: 4915)
CGroup: /system.slice/nginx.service
├─1092 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
├─8831 nginx: worker process
├─8832 nginx: worker process
├─8833 nginx: worker process
├─8835 nginx: worker process
├─8836 nginx: worker process
├─8837 nginx: worker process
├─8838 nginx: worker process
└─8840 nginx: worker process

feb 17 07:52:51 pc01 systemd[1]: Starting A high performance web server and a reverse proxy server...
feb 17 07:52:51 pc01 systemd[1]: Started A high performance web server and a reverse proxy server.
feb 17 09:51:29 pc01 systemd[1]: Reloading A high performance web server and a reverse proxy server.
feb 17 09:51:29 pc01 systemd[1]: Reloaded A high performance web server and a reverse proxy server.
(base) marco@pc01:~$ sudo nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful


Before trying to access the website, I cleaned all the content of the web-browser's cache and history.
The only Google Chrome's extension installed is Vue.js devtools

The DNS provider configuration matches with the Internet Service Provider configuration:
- https://drive.google.com/open?id=1YHhRqMcyHj0wSRVjjtQXOjrO-Zj1wlbz
- https://drive.google.com/open?id=1vk9YEwl_PW4uifFMAo9m5nnkzEFewM7I

The internet connection is working fine.

What aspects, elements, configurations, do I have to check and verify?
How could I solve this problem?
Looking forward to your kind help.
Marco