Hi, On the "action" pane in the Queue Viewer console, When I choose connect to server, I can't select the CAS server, I have only the mailbox servers. Is it usual? Thank you!

Hi CAS servers would not have mail queues on them unless they were pre-Exchange 2013 and they also had the Hub Transport role installed. Cheers, Steve

Thank you, I feel confused. As i know there are two roles in exchange 2013: Mailbox and CAS. Both of them has transport service (front end, backend). Which means that both of them has mail queues isn't it?

No worries Take a look at this article which explains the transport process in 2013: Mail Flow Cheers, Steve

Thank you :)