Hi, When it was the first time to connect to server, the following code works fine. s.lowest_layer().connect(*endpoint_iterator++, error); s.handshake(boost::asio::ssl::stream_base::client, error); When the server connection lost then resumed, the client try to run above code again, the s.lowest_layer().connect(*endpoint_iterator++, error); returned no error of success, but the s.handshake(boost::asio::ssl::stream_base::client, error); hang up. Appreciate any helps? Thank you. - j