How do I make my mail program leave a copy of my messages on the server?
If you use the POP3 protocol to read mail sent to an e-mail mailbox, most programs (such as Outlook) will delete the messages from our mail servers as soon as you read them. This means you can't later use Webmail or another mail program to view the same messages.
Note that this may be what's happening if it appears that messages are being deleted unexpectedly from your Inbox before you get a chance to see them. For example, you might check your mail from several devices and notice that sometimes mail messages don't appear on all of the devices. That can be happening because one of the devices is configured to delete messages from the server immediately after downloading them. Therefore, any other device that checks mail after that won't see those new messages.
It's probably a better idea to set your mail program to leave a copy of the messages on our servers for a few days after it retrieves them. That way, you can view your messages another way if you delete them from your mail program by accident or have other mail program problems.
We have specific pages showing how to set various programs to leave messages on the server. Note that you don't need to follow these instructions if you use IMAP to read mail instead of POP3; IMAP always leaves messages on the server.