mail issue: not sending (addressed to multiple recipients in BCC

Hi,

I am having trouble sending a message to multiple recipients in the BCC field. I am sending to myself in the To: box and many others in BCC. It is not sending the message, either through my Mail program, nor through iCloud mail. iCloud mail gives me "Cannot send message. This message cannot be sent at this time." messge, but no explanation why. (iCloud mail seems to be working normally according to on-line status report). My Mail program give me a, "Cannot send message using the server smtp.me.com:(username)

The server "smtp.me.com" did not recognize the following recipients: [followed by long list of recipients all separated by commas] though it doesn't list all the recipients in the field.

Could it be that I just have too many in the field?

HELP! I'm in a time-crunch on this one.

It did send a test e-mail to me, just fine. No other reipients listed.)