I have put together a group of 340+ email addresses in a group, so of which were pulled from my contact database and some that were entered directly into contact group.

When I go to send, it get an error that pops up that "One or more recipients are invalid".  I have gone through the list and found the @ symbol on each address and the extension is right on all addresses.

The message gets put into my Drafts" folder and does not send to anyone on the list, even the CC'ed addresses, one of which is my own.

How would one figure out which address(s) are causing the problem?

Thanks,
Harvey