Undeliverable BCC mail to Group list

With the new Outlook 2010, there are no longer any restrictions to the number of recipients in each list, so I consolidated my group lists into one. Currently it has about 350 recipients in it.

I tried sending out an email (about 500kb) today to the group list in the bcc field and a single name in the "to" field. An email came back from "System Administrator" with subject : "Undeliverable : (Title of email here)"

In this return email, it says "Your message did not reach some or all of the intended recipients." And thenit proceeded to list the entire group list with a line "None of your e-mail accounts could send to this recipient" below the recipient name and email address.

Can anyone let me know how to fix this?

Whether or not Outlook 2010 has any restrictions of how many people can be in an Email Recipients list doesn't mean there aren't other restrictions put in place by your email provider and or ISP as to how many recipients one email can contain. So your Email provider may limit the number, to stop SPAM, to 20 or 30 recipients or whatever. When it sees an Email that contains 350 email addresses, going out to 350 recipients, it just Blocks and sends back an Administrative warning.

There is only one way to fix it. Find out how many email addresses can be in one email and don't go over that limit. you would need to call your providers tech support.