I'm using ShareX to upload files via a POST request to my website (the file is POSTed to the PHP script). When uploading large files (100+ MB) and sometimes smaller ones (2-3MB) the upload will time out with "Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host." I believe this means LiteSpeed is terminating the connection but I am unsure as how to fix it.
I think you need to set up your modem’s NAT PMP and UPnP ports correctly so that the upload is not limited and the bandwidth will work accordingly. You can do this by typing in you IP address in your browsers address bar and logging in.