Email queue size alert - The exim delivery queue size is 3013

[SecondSight]

Hello ! :)

I'm sending an email to all of my board's members using the ACP bulk mail tool. I've sent 79 750 emails up to now and there are still 2 949 emails to be sent (50 each minute). So it's nearly finished I think...

But :
- I received many emails saying "Mail delivery failed : returning message to user".
- I also received emails saying : "Email queue size alert - The exim delivery queue size is 3013".

Since I don't know anything about all this (I'm reading about it at the moment anyway), I would like to ask you a few questions :
- Should I delete all the messages in queue ?
- Do you think the messages in queue correspond to non valid email adresses ?
- How can I get a list of all the emails which are not valid ?
- Can you advise me about what I should do ?

My server has got WHM/CPanel.

Thank you for your help ! :)

[rct2·com]

Most mail servers systems have code in them to cope with failed delivery. Messages may be rejected for various reasons, and the mail server requeues them to try again later. Each time it queues them for a resend, it puts a longer delay before the next send.

Therefore with a bulk mailing, the requeue can grow quite large, quite quickly. I suspect that it what your message is about.

After a certain number of resends (which is normally configurable), the mail server then usually sends an 'undeliverable' message to the original sender.

If the 'reject' reason is something like 'unknown recipient', then the message doesn't get requeued and you get an immediate failure message like the one you describe.

If I were you, I'd get ready for a flurry of 'failed delivery' messages in your forum email inbox in the next few days.