Question:
When I try to send e-mail to the distribution list, it gets stuck in outbox. What should I do?

Answer:
I’d start by verifying that all of the addresses in the distribution list are correct. A typo or incorrect address may be causing address resolution to fail and thus preventing one or more of the messages from being delivered.

I’d guess that some of the people on the list actually are receiving the message. You’re just seeing the residual message because of that one (or more) recipient whose address is problematic.

Without more information I can’t get a more specific than that.