guys please help
i have a sme 9.0 server running as a mail server
Yup - please update

my problem is that the client is using an outside marketing company to send bulk news messages using mailchimp to the client's staff of 90+ members.
90% of the news messages sent to the staff members from the outside marketing company using mailchimp gets rejected.
You need to look at where and why it is being rejected. Are they bounced by your SME server ?
If the sever is getting mail from a POP3 catch all account, is it being stopped at the ISP or wherever you have the account ?
Can you get some logs or a copy of a bounce mail to see what is happening ?
Please explain your setup a little more clearly and try and find a bounced mail.
B. Rgds
John