Distribution lists

I have two distribution lists. When I send an email to a list it misses off the last few people. A list with 115 on it sends to 70. A list with 15 sends to 10.  Help please!

I have the same problem. Unless I get an answer, I will have to go back to Outlook.

One of the email addresses on the list was wrong format. I found and corrected it and all was well.