You are receiving the message "ML-009 - Too many recipients" because there are too many email addresses listed in theSend to: or Copy To: boxes of your email message. The mail server is unable to send email with as many email addresses as you have entered.
Split the Amount of Recipients
To resolve this issue, you will need to split up the amount of recipients. You need to send more than one email, each with less number of recipients listed in the Send To: or Copy To: box.