The following error can be caused by firewall restrictions. I do not know the specifics of the firewall restrictions, but the TLS connection completes successfully in the prior call to Chilkat.Rest.Connect().    In other words, the TLS handshake completes successfully and then the firewall closes (or blocks) the connection.

 

ChilkatLog:
  FullRequestFormUrlEncoded:
    DllDate: Jul 24 2019
    ChilkatVersion: 9.5.0.79
    UnlockPrefix: Start my 30-day Trial
    Architecture: Little Endian; 32-bit
    Language: ActiveX
    VerboseLogging: 0
    uriPath: /api/security/oauth/token
    autoReconnect: 1
    sendReqFormUrlEncoded:
      sendReqHeader:
        omitContentType: 0
        sendReqHeader2:
          checkEstablishConnection:
            The connection already exists, as far as we know..
          --checkEstablishConnection
        --sendReqHeader2
      --sendReqHeader
    --sendReqFormUrlEncoded
    fullRequestGetResponse:
      Reading response header...
      Failed to read beginning of SSL/TLS record.
      b: 0
      dbSize: 0
      nReadNBytes: 0
      idleTimeoutMs: 30000
      Failed to receive more TLS application data.
      tlsApp: Socket operation timeout.
      elapsedMs: Elapsed time: 30919 millisec
      Failed.
      Failed to read response header.
    --fullRequestGetResponse
    Failed.
  --FullRequestFormUrlEncoded
--ChilkatLog