I've got this:
[info] asio async_read_at_least error: system:10058 (A request to send or receive data was disallowed because the socket had already been shut down in that direction with a previous shutdown call)
[error] handle_read_frame error: websocketpp.transport:2 (Underlying Transport Error)
Fixed it by adding
m_server.pause_reading(handler) before calling
m_server.close on handler.