This question doesn't have to do with Exchange 2013, rather 2003. Sorry if it's in the wrong spot.
I have a user that has created a group in his Outlook 2010. When he sends an email to that group, he receives an "undeliverable" message from an account that is not in our system. It was a past employee from YEARS ago that hasn't had an account on the system for YEARS, and certainly isn't included in the list of names associated with that group.
But it's not just when he sends it to that specific group. He has sent other "group" emails (not specific groups he has set up in Outlook, rather lists of accounts) and received the same undeliverable message. Obviously we're narrowing down the accounts that are on those two lists, but I'm not sure how they relate, because non-group emails get to them fine without generating the undeliverable message.
Does that make sense?
If that is unclear, please let me know and I'll do my best to clarify.
Thanks to everyone in advance for the guidance.