Unfortunately, the POP (Post Office Protocol) protocol is not allowed for connections to Exchange accounts. We do not allow POP3 on the Exchange system for a few reasons:

• The protocol is extremely resource intensive for the mail servers.
• Mail cannot be restored.
• POP3 client applications can only be used to download messages from the e-mail server to a single folder (usually the Inbox) on the client computer.
• The POP3 protocol can't synchronize multiple folders on the e-mail server with multiple folders on the client computer.
• POP3 also doesn't support public folder access.

You can set up a connection to Exchange via IMAP using the settings found at Office 365, Email, Exchange, IMAP Email Access to Exchange