B4J Question [SOLVED]Gmail not working

Zvi · Jun 11, 2023

Hi, I'm trying to send a gmail through a B4J app but it's not working. I've updated my cacerts in Java and tested it with keytool and that's OK.
My code is:

B4X:

Private Sub B4XPage_Created (Root1 As B4XView)
    Root = Root1
    Root.LoadLayout("MainPage")
    smtp.Initialize("smtp.gmail.com", 465, "abc@gmail.com", "defgh", "SMTP")
    smtp.UseSSL = True
End Sub

'You can see the list of page related events in the B4XPagesManager object. The event name is B4XPage.

Private Sub GenerateCodeBtn_MouseClicked (EventData As MouseEvent)
    smtp.To.Add("xxx@gmail.com")
    smtp.Body = "body"
    smtp.Subject = "Test"
    smtp.UseSSL = True
    smtp.StartTLSMode=True
    
    Dim trustall As CustomTrustManager
    trustall.InitializeAcceptAll
    smtp.SetCustomSSLTrustManager(trustall)
    smtp.AuthMethod = smtp.AUTH_LOGIN
    
    smtp.Send
    Log("sending message")
    
End Sub

I tried without using:

B4X:

smtp.StartTLSMode=True

and:

B4X:

Dim trustall As CustomTrustManager
    trustall.InitializeAcceptAll
    smtp.SetCustomSSLTrustManager(trustall)
    smtp.AuthMethod = smtp.AUTH_LOGIN

But got the following error:
javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:128)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:321)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:264)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:259)

when Including:

B4X:

Dim trustall As CustomTrustManager
    trustall.InitializeAcceptAll
    smtp.SetCustomSSLTrustManager(trustall)
    smtp.AuthMethod = smtp.AUTH_LOGIN

I get the error:
java.lang.RuntimeException: Empty writer returned: 530-5.7.0 Authentication Required. Learn more at
530 5.7.0 https://support.google.com/mail/?p=WantAuthError gy15-20020a05600c880f00b003f7f475c3bcsm9887218wmb.1 - gsmtp
at anywheresoftware.b4a.net.SMTPWrapper$1.run(SMTPWrapper.java:312)

and support.google.com/mail/ did not help.

when I add:

B4X:

smtp.StartTLSMode=True

I get an error:
java.net.SocketTimeoutException: Read timed out

When I use my gmail manually it works OK.
Would really appreciate some help.

Erel · Jun 11, 2023

Don't set both UseSSL and StartTLSMode. They are mutually exclusive. Set StartTLSMode and the port should be 587.
Also make sure to enable the "allow less secure apps" option in gmail. It will not work without it.

Zvi · Jun 11, 2023

I found this on Google:
The option of "Less-secure access" for POP3/IMAP/SMTP has been discontinued: https://support.google.com/accounts/answer/6010255

Instead you can enable 2-step verification in your Google account security settings (https://support.google.com/accounts/answer/185839), then generate an application password to use instead of your regular account password (https://support.google.com/accounts/answer/185833).

I'll try that option and then update the forum.

Zvi · Jun 11, 2023

SOLVED
I reinstated 2-step-verification and made an app password for the app.
Now:

B4X:

Private Sub B4XPage_Created (Root1 As B4XView)
    Root = Root1
    Root.LoadLayout("MainPage")
    Dim port=587 As Int
    Dim userName="xxx@gmail.com" As String
    Dim passWord="1234567890123456" As String '16-digit app password generated in Google account
    
    smtp.Initialize("smtp.gmail.com", port, userName, passWord, "smtp")
    smtp.UseSSL = True
End Sub

'You can see the list of page related events in the B4XPagesManager object. The event name is B4XPage.

Private Sub GenerateCodeBtn_MouseClicked (EventData As MouseEvent)
    smtp.To.Add("yyy@gmail.com")
    smtp.Body = "body"
    smtp.Subject = "Test"
    smtp.StartTLSMode = True

    Dim trustall As CustomTrustManager
    trustall.InitializeAcceptAll
    smtp.SetCustomSSLTrustManager(trustall)
    smtp.AuthMethod = smtp.AUTH_LOGIN
    
    smtp.Send

Works perfectly!

Zvi · Jun 11, 2023

Just to clarify, the app password for Gmail is only to be used in this app. It is a 16-digit password generated by Google to replace the google email password only in this specific app.
It does not replace the email password you use to login to Gmail.

AnnnaKiska · Jun 12, 2023

Sorry. Where download smtp library?

Zvi · Jun 12, 2023

Use jnet library for smtp

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