Mailman delays in sending

Hello,

I am running into a mailman problem: There is an unacceptably huge delay in sending a message to a mailing list and actually getting the message sent!

Today I sent a message to a list that took 12 hours to get it actually sent. The list is only 9 subscribers, so load cannot possibly be an issue here. All other emails get processed in a timely manner.

I saw this thread: http://forums.cpanel.net/showthread.php?t=16700 It talks about the same issues, but I am wondering if its still valid as it is about 5 years old.

Is there any way to get mailman under cpanel to process list emails quicker? For a great many things 12 hours is an unacceptable delay for mailing list.

Thanks.