Email AOL Failures
 

I circulated a group email to my neighbors. All the emails with an AOL address failed despite the fact that the email addresses were correct. How do I resolve this issue?

Just a guess on my part. It could be that AOL sees numerous carbon copies and decides it is spam and blows it away.

That's the answer.

What is "AOL"?

Highly likely. Spam and the tactics used to fight it end up impacting quite a bit of perfectly legitimate email.
--
Bob C

Why are you still using AOL? There are so many better Free choices out there.

Were you attaching a photo? There is a file size limit on AOL.

AOL email is free
 

is free, and has all the options of Hotmail, Gmail, etc.

What are those free choices?

Google is your friend. Here is one person's opinion:

The Best Free Email Services of 2016 | Top Ten Reviews

I personally use gmail. The best option, in my opinion, if you don't mind spending a few dollars, is to obtain your own domain so you can have an e-mail address such as:

bill@smith.com
or
bill@smith.me

or something really clever such as

m@ry.com ;-)