Connection timeout from work, working anywhere else

[GuiPoM]

It must have a positive impact, I am now able to access the server using
HTTP, but not using HTTPS.
nginx is running on my raspberry, port 80 for http, for 443 for https.
External ports are routed to according internal ports.

So HTTP is fine, HTTPS still returns an ERR_TUNNEL_CONNECTION_FAILED from my
work computer. But from my phone, it works fine.
Error log is:
2015/04/23 15:04:04 [error] 2151#0: *8964 upstream prematurely closed
connection while reading response header from upstream, client: 109.99.99.99
, server: , request: "GET
/socket.io/?EIO=3&transport=polling&t=1429794125290-15&sid=ZjXxkYkMXrbfNkTbAACm
HTTP/1.1", upstream:
"http://127.0.0.1:8070/socket.io/?EIO=3&transport=polling&t=1429794125290-15&sid=ZjXxkYkMXrbfNkTbAACm",
host: "truc:4321", referrer: "https://truc:4321/jeedom/index.php?v=m&"

Something that could help, maybe: I notice that referrer is a hostname, some
for host, but I am accessing with an ip address. Is it expected ?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,258187,258320#msg-258320