Unable to open session channel

Hi CK - I'm currently unable to open a session channel. Keep getting the message - "Payload is empty". I'm thinking this could have to do with the server we're trying to access (Win32 port of SSH 7.1), yet the authentication seems to be going through fine. See lastErrorText below.

ChilkatLog:
  OpenSessionChannel:
    DllDate: Dec 30 2015
    ChilkatVersion: 9.5.0.55
    UnlockPrefix: Anything for 30-day trial
    Architecture: Little Endian; 64-bit
    Language: Cocoa Objective-C
    VerboseLogging: 0
    SshVersion: SSH-2.0-OpenSSH_7.1p1 Microsoft_Win32_port_with_VS
    openSessionChannel:
      sshTransportOpenChannel:
        channelType: session
        clientChannel: 0
        clientInitialWindowSize: 327680
        clientMaxPacketSize: 8192
        Sent open channel request
        sshReadMessage:
          Payload is empty
        --sshReadMessage
        Error reading channel response.
      --sshTransportOpenChannel
      channelNum: -1
    --openSessionChannel
  --OpenSessionChannel
--ChilkatLog

Any ideas?