You want to check your email from your iPad outside of the office. When you are back in the office, you want to use your regular PC or Mac to access your email. So both PC and iPad are accessing the same mailbox. When two or more computers are accessing the same mailbox, you will encounter an access conflict and one that comes later than the other are kicked out.
This problem does not happen when you are using so called IMAP email server, but many of us who use POP3 email server will encounter this problem. This problem caught my attention when I got my iPad. iPad was grabbing the mailbox and not letting it go making my desktop unable to access my email.
So I asked our top engineer (guru) to look into this problem. He just released the upgrade version of our POP3 service. I don't know how he did it, he solved the problem and I can now share same mailbox with my iMac and iPad. This upgrade will be available next week to all our customers at www.DreamersI.net.