The underlying connection was closed: An unexpected error occurred on a receive. Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

This error means that the computer at the other end of the connection closed it. If you're trying to link to another piece of software, that probably means that your authorisation wasn't correct, or you violated the protocol it was expecting. You would do better asking the user community for the software you're trying to use, and describing what you are actually doing - your question provides essentially no information and is therefore impossible to answer.