The proxy fucks up badly, it swallows your PORT command. Unless proxy configuration is fixed, you will continue to get that error.
The Bluecoat thing is acting as a man-in-the-middle, but it has a bug or configuration issue. Not forwarding the PORT command to the server throws the challenge-response system out of sequence. The server doesn't know where to connect to and send the data.
The Bluecoat thing is acting as a man-in-the-middle, but it has a bug or configuration issue. Not forwarding the PORT command to the server throws the challenge-response system out of sequence. The server doesn't know where to connect to and send the data.