I have worked since version 5.6, and never found the option to authenticate sender using a pop client such as (Thunderbird, Outlook....), internal user does not have problem cause connection is direct to the mail server, but roaming user outside the network which in fact are the most needed to authenticate always present error message where server can authenticate them.
Does anyone knows a workaround to solve this problem where the MEG in proxy authenticate roamig users?
Looking foward to your answers.
MEG is able to proxy and scan POP3 traffic. It can be the target for your roaming users and then make the connection in to your server. See the admin guide for more details on configuration of this in MEG.