Can't use the "reply all" feature

[skapsak]

When i get a message from outside my organization, I can &quot;reply&quot; to the sender without issue. If however, there are CCs, my email for some reason cuts off the domain names and shows only the aliases that were in the senders address book. My email system looks to our internal sever for matches to the aliases and obviously can't find them.&nbsp;&nbsp;They come back marked as undeliverable.&nbsp;&nbsp;Is there a setting that I can change or is it something that is set up at the network level.&nbsp;&nbsp;I have looked at all of the preference settings.<br><br>thanks