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Question:

VerifySMTPConnection working with VB6 but not with .NET

Sep 19 '17 at 12:01

Hello.

I have a license for both the ActiveX and for the .NET version of Chilkat.

For both I'm using exactely the same ChilkatMail properties. With VB6, it works fine, but the same code fails in VB.NET in the function "VerifySMTPConnection".

Here is the LastError log for VB6:

  * VerifySMTPConnection:1
ChilkatLog:
  VerifySmtpConnection:
    DllDate: Jun 10 2014
    ChilkatVersion: 9.5.0.40
    UnlockPrefix: MYCHILKATUNLOCKKEY
    Username: MYUSER-PC:MyUser
    Architecture: Little Endian; 32-bit
    Language: ActiveX
    VerboseLogging: 0
    Checking TCP/IP connectivity to the SMTP server.
    This does not check the login/password.
    AutoFix: SMTP port 465 is typically for implicit SSL/TLS.
    To prevent auto-fix, set the AutoFix property = False/0
    Checking connectivity to SMTP server smtp.gmail.com:465
    smtp_host: smtp.gmail.com
    smtp_port: 465
    socket2Connect:
      connect2:
        connectImplicitSsl:
          checkServerCert:
            Not verifying server certificate...
            Set the RequireSslCertVerify property to enable verification.
          --checkServerCert
          Secure Channel Established.
        --connectImplicitSsl
      --connect2
    --socket2Connect
    SmtpCmdResp: 220 smtp.gmail.com ESMTP 5sm543244wrb.9 - gsmtp
    ESMTP server smtp.gmail.com:465 is reachable
    checkSmtpConnection: Elapsed time: 234 millisec
    Success.
  --VerifySmtpConnection
--ChilkatLog

And this is the log for VB.NET:

* VerifySMTPConnection:False
ChilkatLog:
  VerifySmtpConnection:
    DllDate: Aug 30 2017
    ChilkatVersion: 9.5.0.69
    UnlockPrefix: MYCHILKATUNLOCKKEY
    Architecture: Little Endian; 32-bit
    Language: .NET 4.6
    VerboseLogging: 0
    AutoFix: SMTP port 465 is typically for implicit SSL/TLS.
    To prevent auto-fix, set the AutoFix property = False/0
    smtpConnectAndAuthenticate:
      smtpConnect:
        smtpHostname: smtp.gmail.com
        smtpPort: 465
        connectionIsReady:
          Need new SMTP connection
        --connectionIsReady
        smtpSocketConnect:
          socketOptions:
            SO_SNDBUF: 262144
            SO_RCVBUF: 4194304
            TCP_NODELAY: 1
            SO_KEEPALIVE: 1
          --socketOptions
        --smtpSocketConnect
        smtpGreeting:
          readSmtpResponse:
            SmtpCmdResp: 220 smtp.gmail.com ESMTP t37sm617192wrc.28 - gsmtp
          --readSmtpResponse
        --smtpGreeting
        startTLS:
          sendCmdToSmtp:
            SmtpCmdSent: EHLO MYUSER-PC<crlf>
          --sendCmdToSmtp
          readSmtpResponse:
            SmtpCmdResp: 250-smtp.gmail.com at your service, [178.203.233.193]
            SmtpCmdResp: 250-SIZE 35882577
            SmtpCmdResp: 250-8BITMIME
            SmtpCmdResp: 250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH
            SmtpCmdResp: 250-ENHANCEDSTATUSCODES
            SmtpCmdResp: 250-PIPELINING
            SmtpCmdResp: 250-CHUNKING
            SmtpCmdResp: 250 SMTPUTF8
          --readSmtpResponse
          sendCmdToSmtp:
            SmtpCmdSent: STARTTLS<crlf>
          --sendCmdToSmtp
          readSmtpResponse:
            SmtpCmdResp: 530-5.5.1 Authentication Required. Learn more at
            SmtpCmdResp: 530 5.5.1  https://support.google.com/mail/?p=WantAuthError t37sm617192wrc.28 - gsmtp
          --readSmtpResponse
          Non-success STARTTLS response.
        --startTLS
      --smtpConnect
    --smtpConnectAndAuthenticate
    Failed.
  --VerifySmtpConnection
--ChilkatLog

What am I doing wrong here?

I'm also attaching my code.

This is the VB6 code:

Option Explicit

Private Sub Form_Load()

 Dim ch As New Chilkat_v9_5_0.ChilkatMailMan
 ch.UnlockComponent m_sUnlockKey

 ch.AutoFix = 1
 ch.MailHost = "pop.gmail.com"
 ch.MailPort = 995
 ch.PopUsername = m_sUserName
 ch.PopPassword = m_sPass
 ch.SmtpHost = "smtp.gmail.com"
 ch.SmtpPassword = m_sPass
 ch.SmtpUsername = m_sUserName
 ch.SmtpPort = 465
 ch.SmtpAuthMethod = ""
 ch.PopSsl = 1
 ch.Pop3SPA = 0
 ch.StartTLS = 1
 ch.SmtpSsl = 1

 Debug.Print "mailhost: " & ch.MailHost
 Debug.Print "mailport: " & ch.MailPort
 Debug.Print "popusername: " & ch.PopUsername
 Debug.Print "poppassword: " & ch.PopPassword
 Debug.Print "smtphost: " & ch.SmtpHost
 Debug.Print "smtppassword: " & ch.SmtpPassword
 Debug.Print "smtpusername: " & ch.SmtpUsername
 Debug.Print "smtpport: " & ch.SmtpPort
 Debug.Print "smtphost: " & ch.SmtpHost
 Debug.Print "smtpauthmethod: " & ch.SmtpAuthMethod
 Debug.Print "popssl: " & ch.PopSsl
 Debug.Print "pop3spa: " & ch.Pop3SPA
 Debug.Print "starttls: " & ch.StartTLS
 Debug.Print "smtpssl : " & ch.SmtpSsl

 Dim bVerifyPopConnection As Boolean
 Dim bVerifyPopLogin As Boolean
 Dim bVerifySmtpConnection As Boolean
 Dim bVerifySmtpLogin As Boolean

 Dim sErrVerifyPopConnection$
 Dim sErrVerifyPopLogin$
 Dim sErrVerifySmtpConnection$
 Dim sErrVerifySmtpLogin$

 Dim m_sMailReport$
 m_sMailReport = ""

 'Test incoming
 Dim lRetInCon&
 Dim sRetInCon$
 lRetInCon = ch.VerifyPopConnection
 sRetInCon = ch.LastErrorText
 bVerifyPopConnection = CBool(lRetInCon)
 m_sMailReport = m_sMailReport & "* VerifyPopConnection:" & lRetInCon & vbNewLine & pCleanMailReport(sRetInCon) & vbNewLine & vbNewLine

 Dim lRetInLogin&
 Dim sRetInLogin$
 lRetInLogin = ch.VerifyPopLogin
 sRetInLogin = ch.LastErrorText
 bVerifyPopLogin = CBool(lRetInLogin)
 m_sMailReport = m_sMailReport & "* VerifyPopLogin: " & lRetInLogin & vbNewLine & pCleanMailReport(sRetInLogin) & vbNewLine & vbNewLine

 'Test outgoing
 Dim lRetOutCon&
 Dim sRetOutCon$
 lRetOutCon = ch.VerifySmtpConnection
 sRetOutCon = ch.LastErrorText
 bVerifySmtpConnection = CBool(lRetOutCon)
 m_sMailReport = m_sMailReport & "* VerifySMTPConnection:" & lRetOutCon & vbNewLine & pCleanMailReport(sRetOutCon) & vbNewLine & vbNewLine

 Dim lRetOutLogin&
 Dim sRetOutLogin$
 lRetOutLogin = ch.VerifySmtpLogin
 sRetOutLogin = ch.LastErrorText
 bVerifySmtpLogin = CBool(lRetOutLogin)
 m_sMailReport = m_sMailReport & "* VerifySMTPLogin:" & lRetOutLogin & vbNewLine & pCleanMailReport(sRetOutLogin) & vbNewLine & vbNewLine

 Debug.Print m_sMailReport

End Sub

Private Function pCleanMailReport(ByVal value As String) As String

    Dim s As String
    s = value
    s = Replace(s, m_sUserName, "<MYUSERNAME>")
    s = Replace(s, m_sPass, "<MYPASSWORD>")
    s = Replace(s, m_sUnlockKey, "MYCHILKATUNLOCKKEY")

    pCleanMailReport = s

End Function

And this is my VB.NET code:

Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Dim ch As New Chilkat.MailMan
    ch.UnlockComponent(_sUnlockKey)

    ch.AutoFix = True
    ch.MailHost = "pop.gmail.com"
    ch.MailPort = 995
    ch.PopUsername = _sUserName
    ch.PopPassword = _sPass
    ch.SmtpHost = "smtp.gmail.com"
    ch.SmtpPassword = _sPass
    ch.SmtpUsername = _sUserName
    ch.SmtpPort = 465
    ch.SmtpAuthMethod = ""
    ch.PopSsl = True
    ch.Pop3SPA = False
    ch.StartTLS = True
    ch.SmtpSsl = True

    Debug.Print("mailhost: " & ch.MailHost)
    Debug.Print("mailport: " & ch.MailPort)
    Debug.Print("popusername: " & ch.PopUsername)
    Debug.Print("poppassword: " & ch.PopPassword)
    Debug.Print("smtphost: " & ch.SmtpHost)
    Debug.Print("smtppassword: " & ch.SmtpPassword)
    Debug.Print("smtpusername: " & ch.SmtpUsername)
    Debug.Print("smtpport: " & ch.SmtpPort)
    Debug.Print("smtphost: " & ch.SmtpHost)
    Debug.Print("smtpauthmethod: " & ch.SmtpAuthMethod)
    Debug.Print("popssl: " & ch.PopSsl)
    Debug.Print("pop3spa: " & ch.Pop3SPA)
    Debug.Print("starttls: " & ch.StartTLS)
    Debug.Print("smtpssl : " & ch.SmtpSsl)

    Dim _sMailReport As String = String.Empty

    'Test incoming
    Dim bRetInCon As Boolean = ch.VerifyPopConnection()
    Dim sRetInCon As String = ch.LastErrorText

    _sMailReport = _sMailReport & "* VerifyPopConnection:" & CStr(bRetInCon) & Environment.NewLine & pCleanMailReport(sRetInCon) & Environment.NewLine & Environment.NewLine

    Dim bRetInLogin As Boolean = ch.VerifyPopLogin()
    Dim sRetInLogin As String = ch.LastErrorText
    _sMailReport = _sMailReport & "* VerifyPopLogin: " & CStr(bRetInLogin) & Environment.NewLine & pCleanMailReport(sRetInLogin) & Environment.NewLine & Environment.NewLine

    'Test outgoing
    Dim bRetOutCon As Boolean = ch.VerifySmtpConnection()
    Dim sRetOutCon As String = ch.LastErrorText
    _sMailReport = _sMailReport & "* VerifySMTPConnection:" & CStr(bRetOutCon) & Environment.NewLine & pCleanMailReport(sRetOutCon) & Environment.NewLine & Environment.NewLine

    Dim bRetOutLogin As Boolean = ch.VerifySmtpLogin()
    Dim sRetOutLogin As String = ch.LastErrorText
    _sMailReport = _sMailReport & "* VerifySMTPLogin:" & CStr(bRetOutLogin) & Environment.NewLine & pCleanMailReport(sRetOutLogin) & Environment.NewLine & Environment.NewLine

    Debug.Print(_sMailReport)

End Sub
Private Function pCleanMailReport(ByVal value As String) As String

    Dim s As String = value
    s = Replace(s, _sUserName, "<MYUSERNAME>")
    s = Replace(s, _sPass, "<MYPASSWORD>")
    s = Replace(s, _sUnlockKey, "MYCHILKATUNLOCKKEY")

    Return s

End Function

End Class

The debug messages (Debug.Print("mailhost: " & ch.MailHost), etc.) show me that all properties of the ChilkatMail are set to the same in VB6 and in VB.NET.

---

Answer

The strange thing is that - although VerifySMTPConnection fails - sending a mail in VB.NET works with this sample:

https://www.example-code.com/vbdotnet/smtp_gmailSsl.asp

So maybe it's a bug in the ChilkatDotNet because in VB6 "VerifySMTPConnection" works just perfectly.

Doesn't anybody else have this problem?

---

Answer

What I've noticed is that in the VB6 example, after setting STARTTLS to TRUE, it stays TRUE. In the VB.NET example, I set it to TRUE as well, but it keeps staying FALSE.

---

Answer

Hmmm, I just noticed that even on VB6, VerifySMTP connection doesn't succeed.

I'll check further first.

---

Answer

Ok, I now found out that if I just run the line

Dim bVerifySmtpConnection As Boolean = ch.VerifySmtpConnection()
or (for VB6):
lRetOutCon = ch.VerifySmtpConnection

twice, the first attempt will fail while the second one will succeed.

What might cause this?