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Question:

Sending Email via outlook.office365.com

Jul 02 '14 at 19:28

I get the following error when trying to send email using outlook.office365.com

ChilkatLog:
  SmtpNoop:
    DllDate: Aug 15 2013
    ChilkatVersion: 9.4.1.42
    UnlockPrefix: 
    Username: 
    Architecture: Little Endian; 32-bit
    Language: ActiveX
    VerboseLogging: 1
    SmtpConnect:
      SmtpHost: outlook.office365.com
      SmtpPort: 587
      SmtpUsername: *                                                                                                                                          

      SmtpSsl: 1
      StartTLS: 1
      Need new SMTP connection
      checkForExistingConnection: Elapsed time: 0 millisec
      SMTP_Connect:
        Connecting to SMTP server outlook.office365.com:587
        smtp_host: outlook.office365.com
        smtp_port: 587
        smtp_user: *
        ConnectTimeoutMs_1: 30000
        calling ConnectSocket2
        IPV6 enabled connect with NO heartbeat.
        connectingTo: outlook.office365.com
...
        connect successful (1)
        clientHelloMajorMinorVersion: 3.1
        buildClientHello:
          majorVersion: 3
          minorVersion: 1
          numRandomBytes: 32
          sessionIdSize: 0
          numCipherSuites: 10
          numCompressionMethods: 1
        --buildClientHello
        readIncomingTls_serverHello:
          readTlsRecord:
            v50.48, ct=50, sz=8258
            Timeout waiting to read socket or accept connection
            timeoutMs: 30000
            Failed to read TLS record (2)
            tlsRec_msg: 104
            msgLen: 8258
          --readTlsRecord
        --readIncomingTls_serverHello
        Expected ServerHello but did not receive it.
        Client handshake failed. (3)
        Failed to connect to SMTP server.
      --SMTP_Connect
      smtpConnect: Socket timeout.
      checkOrMakeSmtpConnection: Elapsed time: 30186 millisec
    --SmtpConnect
    Failed to connect to SMTP server
  --SmtpNoop
--ChilkatLog

---

Answer

Port 587 is the explicit SSL/TLS port for the SMTP protocol. The implicit SSL/TLS port is 465. The difference between implicit SSL and explicit SSL is that for implicit, the SSL handshake begins immediately after establishing the TCP socket connection. For explicit SSL, the SSL handshake (i.e. the conversion of the TCP socket connection to an SSL/TLS secure channel) happens when the SMTP client explicitly sends a command to the server to initiate the SSL handshake. In the SMTP protocol, this happens with the "STARTTLS" SMTP command.

Therefore, to use explicit SSL with port 587, set the mailman.StartTLS property = 1 (which is for explicit SSL/TLS), but leave the mailman.SmtpSsl property = 0 (which is for implicit SSL/TLS). It never makes sense to set both the SmtpSsl and StartTLS properties = 1.