If you can access your Yahoo! Business Email messages using your POP mail client, but your messages do not appear in your mailbox when you access your account using the Yahoo! interface, you most likely need to adjust your POP configuration. Most mail clients give you the option to leave copies of messages you download to your computer on the mail server to which they were delivered.

In this case, you'll want to change your settings to leave copies of your messages on the Yahoo! Mail server instead of deleting them after you have received the messages in your POP mail client. When you leave copies of mail on the server, you can delete them manually using the Yahoo! interface. Learn more.