I have migrated Exchange Server 2010 to 2013 all seems good but when i connect Outlook with POP3, it's give me error like below, :
"Log onto incoming mail server (POP3): Your e-mail server rejected your login. Verify your user name and password for this account in Account Settings. The server responded: -ERR Server Unavailable. 21"
and I have also attached screen shots with this email.