net::ERR_CONNECTION_REFUSED . How to correctly configure Nginx with Socket.io?

[MarcoI]

I add more information and a question:

>From within the PC-Server:

    (base) marco at pc:~$ curl -Iki
https://localhost/sockjs-node/info?t=1580397983088
    HTTP/2 405 
    server: nginx/1.14.0 (Ubuntu)
    date: Fri, 31 Jan 2020 08:19:02 GMT
    allow: OPTIONS, GET

>From the laptop:

    (base) marco at marco-U36SG:~$ curl -Iki
https://ggc.world/sockjs-node/info?t=1580397983088
    HTTP/1.1 405 Method Not Allowed
    Server: nginx/1.14.0 (Ubuntu)
    Date: Fri, 31 Jan 2020 09:34:59 GMT
    Connection: keep-alive
    Allow: OPTIONS, GET

What does it mean "HTTP/1.1 405 Method Not Allowed" ?

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,286850,286872#msg-286872