Nginx odoo 16 proxy and connect() failed (111: Connection refused)

I’ve got these in the log file on odoo nginx proxy:

connect() failed (111: Connection refused) while connecting to upstream, client: 8**.**.**.***, server: bit ****.dns.org, request: "GET /websocket HTTP/1.1", upstream: "http://127.0.0.1:8072/websocket", host: "www.bit***.dns.org"

root@bi:/var/log/nginx#

Another error when I tried to access

"GET /websocket HTTP/1.1" 502 575

I needed to change /etc/hosts form : #127.0.0.1 localhost to 127.0.0.1 bit****.dns.org

Becouse i need to get a certificate with certbot.

My configuration on nginx is

# Odoo Upstreams

upstream odooserver {

    server 127.0.0.1:8069;

}

upstream odoochat {

server  127.0.0.1:8072;

}

map $http_upgrade $connection_upgrade {

default upgrade;

'' close;

}

location /websocket {

proxy_redirect off;

proxy_read_timeout 720s;

proxy_connect_timeout 720s;

proxy_send_timeout 720s;

# Add Headers for odoo proxy mode

proxy_set_header X-Forwarded-Host $host;

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

proxy_set_header X-Forwarded-Proto $scheme;

proxy_set_header X-Real-IP $remote_addr;

#added 95-a 98

proxy_set_header Upgrade $http_upgrade;

proxy_set_header Connection "Upgrade";

proxy_pass http://odoochat;

  }

Why connect() failed (111: Connection refused) ?

Thanks