Email error sending lots of emails at once.


Well-Known Member
Dec 11, 2007
Hi.. This may not relate to cpanel but I wanted to make sure that I may not have something configured wrong. Its a ecent occurence though.

I have a customer that is trying to send an email to about 60 to 70 people. It seems that nearly all the emails sent to gmail and tiscali/talktalk bounced with a similar error. I've done some searching but found very little helpful info. Below are some examples of the bounce messages.

451-4.3.0Multiple destination domains per transaction is unsupported. Please <<< 451 4.3.0 try again. f62si28010951yhh.129 <[email protected]>... Deferred: 451-4.3.0 Multiple destination domains per transaction is unsupported. Please RCPT To:<[email protected]>

421 #4.4.5 Too many connections to this host.
... while talking to

452 #4.5.3 Too many recipients.
<[email protected]>... Deferred: 452 #4.5.3 Too many recipients.
RCPT To:<[email protected]>​

I also have another customer that sends a maling list that has 15k emails on it that has been complaining about a lot more bounces for the last few emails sent, which may be related but so far he hasn't sent me any useful bounce messages, but I suspect may be related.

Can anyone help me resolve the issue? Is it likley to be a problem with the server setup or something else?