I have no clue why it is not working. So I took the computer from my office location and I did the test from another location, with a standard internet access: I have no issue at all.

It means that only the network between the computer and the nginx server makes this error appears, it must have nothing to do with the computer.

I am still hoping to find some help here. I am pretty sure that the <host: "truc:4321", referrer: "https://truc:4321/jeedom/index.php?v=d&p=history"> is causing this issue, but I have no idea if this is a configuration of the nginx server and if I can do something around that.

Please help ! Thx.
GuiPoM