Which server is configured to retrieve emails with the Retrieve email messages action?

The correct answer is the IMAP server. IMAP, or Internet Message Access Protocol, is specifically designed for retrieving and managing emails from a mail server. It allows users to access their email from multiple devices, as it synchronizes the messages between the server and the client, ensuring that any changes made (such as reading an email or deleting it) are reflected across all devices accessing that email account.

This action is essential in scenarios where users need to manage their emails efficiently, allowing applications to retrieve, read, and process email messages without changing their state on the server. The protocol facilitates the retrieval of messages while ensuring that the original email content remains available on the server for continued access.

In contrast, an SMTP server is primarily used for sending emails, not retrieving them. FTP servers are designed for file transfer, and while Exchange servers can handle both sending and receiving emails, they typically implement IMAP or other protocols (like Exchange ActiveSync) for accessing the mailbox. Thus, in the context of the Retrieve email messages action, an IMAP server is the correct choice since it is specifically tailored for the retrieval of emails.