[Mailman-Users] Mailman, Qmail -> Large Message Lost

I am running

• Mailman 2.1.9
• Qmail
• CentOs
• MySQLdb module

I have been able to successfully send a mail to my list members, who are stored in a MySQL, database. This worked when there were eight members. Now that I'm trying it on a production level with approx. 200 members it doesn't work...or, at least, it hasn't after the first 45 min.

SMTP_MAX_RCPTS = 500

There are currently only 157 members in my list.

/var/qmail/concurrencyremote is 250

/var/qmail/concurrencylocal is 30

Could anyone help me improve this performance?