Hitting some sort of bulk limit with CDO?

[GraeagleBill]

In executing a CDO mailing function in my app, I hit the -2147220975 error condition after having successfully sent out 81 emails. With a data-point setting, I resumed the function continuing at the point of the first failure only to hit the same error after 83 emails. I know of no limits with CDO. The body of the emails are just a couple of lines plus a URL, so size ought not be the issue. There are no attachments. The app uses the Google Gmail "App Password" as authority to use the IMAP.Gmail.Com server.

[Micron]

Don't email servers often have user account based limits to stop runaway emailing (especially when generated via code)? I'd check with the server admin.

[Welshgasman]

https://www.quora.com/What-is-the-li...-mail-on-Gmail

[Micron]

I saw CDO and my eyes glazed - didn't see it was GMail so forget the admin idea.

[GraeagleBill]

I notice that the failing client uses the "App Password" along with the server Imap.Gmail.com, while all my development testing relied on SMTP.GoogleMail.com. Google documents the difference:

1. What's the difference between IMAP and SMTP? The short answer is that IMAP connects to your email providers' server and is used for receiving email while SMTP is used for sending mail to other servers.


2. IMAP is used to retrieve messages, and SMTP is for sending data. IMAP works between the server and client for communication, and SMTP works between servers to transfer information. IMAP allows users to organize emails onto the server, while SMTP allows organizing emails on client storage.

As soon as I have access to the client machine, I'll change the authorization properties to use SMTP.GoogleMail.com and resume at one record past the failure. I think there's a total of 315 records in the queue. (164 already sent successfully)


EDIT: App resumed and sent out another 89 emails using SMTP.GoogleMail.com server before again failing with same error. Welshgasman's reference suggests there's a 500 per day limit for personal email accounts. Since the current OP is dealing with a recordset containing only 315 records, I wouldn't expect any issues as compared with the 500 limit. I remain in mystery with OP unresolved.

[Gicu]

Can you please show us the description for the

-2147220975 error condition

? And the code you're using would be helpful, as there might be some other causes to this error?

Cheers,

[GraeagleBill]

Another item of interest, at least from my point-of-view, is that last week this same app sent out 137 emails with double attachments without any issues whatsoever. EDIT: 2/4 Could this issue be related to the version of Windows? The 137 emails noted were sent from a Windows 11 system, whereas the issue sited in the OP occurred on a clients Window 10 system. My understanding is the CDO is an API to the Windows MAPI, putting the issue partially in the system realm?

The snippet of code that initiates the "send":

    DoCmd.Hourglass True
    
    With rsNewsLtr
    If .RecordCount > 0 Then
        .MoveFirst
            While Not .EOF
            strRecipient = ![e-MailAddr]
            strFName = !FirstName
            strLName = !LastName
            If bolBdyTxtOnly <> True Then
                If bolCont = True Then Call SendUsingCDOMail(strSubj, strRecipient, "Dummy", Replace(strMsgBody, "NnNnNnNn", strFName))
            End If
            intNLCount = intNLCount + 1
            .MoveNext
            Wend
    End If
    
    End With
    
    DoCmd.Hourglass False

Screenshot of the error:


The CDO module I use: (Mixture of my code mixed with Paul's)

Public Sub SendUsingCDOMail(strSubj, strToEMA, strAttName, strBody)
'*=*=*=*=*=(12/27/2022 Code courtesy of Paul Baldarelli)=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
'  E.g., SendMail("TMS Offerings for 2022", "wcsreno@gmail.com", strStmtPDFName, strBody)
'*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
    Dim mail    As CDO.message
    Dim config  As CDO.Configuration
    Dim strAuthSender As String
    Dim strReplyTo As String
    Dim strAttmts() As String
    Dim I As Integer
    
    Set mail = CreateObject("CDO.Message")
    Set config = CreateObject("CDO.Configuration")
    
    config.Fields(cdoSendUsingMethod).Value = cdoSendUsingPort
    config.Fields(cdoSMTPServer).Value = Nz(DLookup("CDOSMTP", "InstProperties"))
    config.Fields(cdoSMTPAuthenticate).Value = 1
    strReplyTo = Nz(DLookup("CDOReplyTo", "InstProperties"))
    strAuthSender = Nz(DLookup("CDOEMA", "InstProperties"))
    config.Fields(cdoSendUserName).Value = strAuthSender
    config.Fields(cdoSendPassword).Value = GetAppPW(Nz(DLookup("CDOPW", "InstProperties")))
    config.Fields(cdoSMTPServerPort).Value = 465
    config.Fields(cdoSMTPUseSSL).Value = True
    config.Fields.Update
    
    Set mail.Configuration = config


    With mail
        .To = strToEMA
        .From = strAuthSender
        .ReplyTo = strReplyTo
        .Subject = strSubj
        .TextBody = strBody
        If (strAttName <> "Dummy") And (Not IsNull(strAttName)) Then
            strAttmts = Split(strAttName, ";")
            For I = 0 To UBound(strAttmts)
                If Len(Dir(strAttmts(I))) > 0 Then
                    .AddAttachment strAttmts(I)
                Else
                    MsgBox "Specified attachment " & strAttmts(I) & " not found."
                    Exit Sub
                End If
            Next I
        End If
        .send
    End With
    
    Set config = Nothing
    Set mail = Nothing
    
End Sub

[isladogs]

I've used CDO email for years without ever having issues of this kind.
When i was still teaching, CDO was used to send bulk emails, sometimes to all staff which in a large school could easily exceed 300.
That always worked fine though of course it was normally within an organisation.

As for bulk email to external addresses, I've always used a multimailer app such as Mailchimp or SamLogic Multimailer.
These process emails in batches to prevent any limitations on numbers imposed to restrict spammers.

When trying to do bulk email yourself, you may well find the limit varies depending on the server, time of day etc, etc...
In other words, you can't predict when the process will crash. So limit the number you send at once or use a bulk email app as above
I very much doubt the use of CDO is in any way relevant to the issue

However the error message above is explained in the documentation accompanying my example app which I believe you have a copy of.

[GraeagleBill]

Thanks Colin. I will pursue the idea of using a bulk mailer as you suggest. I too did not believe that CDO had much to do if anything with the issue sited in the OP.
Thanks again,
Bill

[isladogs]

For info, this message is from the help file accompanying my CDO app