OK, I am not sure what "remot3dir" represents here. You should have both a proxy server URL and a port. However, the fact that both of your remot3.it connections work OK indicate that there is not a problem with remot3.it and rather it's something about your nginx configuration that needs to be debugged. I'm not an expert in nginx and there are many different things you can do to its configuration.
If it helps, know that on the server side (where the daemon is installed), remot3.it traffic appears to be coming from localhost, or 127.0.0.1.
I'd suggest looking at the nginx log file to see what it thinks is happening when you make remot3.it vs. a direct LAN connection.