How to handle error 452 - 4.3.1 Insufficient system resources

[Clément 148]

Hi,

I'm using ICS 8.68 and Delphi XE.
This Windows Service checks for emails every minute, and send all emails that are found.
The SMTP server is replying with 452 - 4.3.1  Insufficient system resources after a while.
If my customer restart the service ( takes a little over a minute ), another batch of emails are sent without errors ( Same server, same port) Until I receive the error 452 again.

From his point of view, my application has a problem, since a service restart solves the problem. From mine, the SMTP server, which might be shared with other applications, has some issues, either disk space or memory.

 

The service does a lot of other things and all of them are working fine ( no errors in any log).

Should I abort sending emails when this the SMTP server replies with this error? How can I trap it?

 

TIA,

Clément

 

[Lajos Juhász 295]

Google returns that usually this error message occurs when the Exchange server is low on disk space. In any case you should incorporate a delay. Nowdays servers usually has a hard limit how many e-mails you can send in an hour.

[Angus Robertson 577]

Agree, essentially nothing to fix in ICS, it's a server issue, Google brings up a vast number of responses for the error in Exchange.  Hard to tell if it's a real problem with the server being overwhelmed or artificial because it considers the email volume abusive. 

 

Restarting your service merely causes a delay in sending email so the server is content again. 

 

So you need to slow down the rate at which you send emails.  Perhaps send one email per session, if you are sending multiple emails with one connection, Or just wait a second or two between emails, If you get an error sending email, close the session and start a new session.  Much easier to test if you have access to the real server.

 

Are you using the TIcsMailQueue component?  It is designed for this sort of activity and will retry emails that fail on a schedule over many hours.  But it does not currently have a means to so down flow to one server.   It will use multiple servers if one gives an error.

 

Angus

 

 

 

 

 

[Clément 148]

Sorry if I make it sound like was an ICS issue.
It's an internal SMTP server ( I don't know which ). I ask their IT folks to help me with some information, but this time of the year emails must be sent, and since most IT fellows are in holidays....

 

Getting back to ICS, is there a "better" event to add some delay ( emails per hour throttle comes to my mind )

 

procedure TRNBWSMTP.SmtpRequestDone(Sender: TObject; RqType: TSmtpRequest;
  ErrorCode: Word);
begin
   if not fDebugMode then
     Log(FSMTP.LastResponse); // This is where it logs the error 452

  
   if (ErrorCode > 0) and  (ErrorCode < 10000) then
   begin
     Log('RequestDone Rq=' + IntToStr(Ord(RqType)) + ' Error='+ FSMTP.ErrorMessage);
     if ErrorCode = 501 then
     begin
       FSuccess := false;
       FSMTP.Quit;
       exit;
     end;
   end;
                                              
   {...}
end;                                              

 

 

[programmerdelphi2k 237]

I dont know like ICS works, but if you use a "var-Flag" to controls the time send.. like: 

Quote

IF NoSendForWhilePleaseWaitAtime then Exit;

...

the error appears on "LOG save"? then, not on "send" in fact?

Edited December 28, 2022 by programmerdelphi2k

[Angus Robertson 577]

ICS is mostly even driven, you never put delays in events since that upsets the protocol. 

 

So it's really down to how you queue your emails, delay sending them after an error, I mostly use triggers tested in a single once per second timer event, there are several functions in ICS for setting and checking triggers.  Except for TIcsMailQueue which uses real date/times checked in a thread.

 

How many emails (megs) are you sending each minute?  It must be a lot to cause the mail server queue to run out of disk space continually. 

 

Angus

 

[Clément 148]

21 minutes ago, Angus Robertson said:

ICS is mostly even driven, you never put delays in events since that upsets the protocol. 

The routine is working fine, and I really don't want to upset the protocol.

 

22 minutes ago, Angus Robertson said:

How many emails (megs) are you sending each minute?  It must be a lot to cause the mail server queue to run out of disk space continually. 

I asked for this information. Unfortunately most IT folks are in holiday break. My best guess: this SMTP server is share among other applications.

 

I'm placing a delay before the initial call to connect (or MailForm).