Whenever your email program is setup to leave a copy of your email on the mail server, it will slowly begin to fill up your alloted space on the server. Once your space reaches the MAX space alloted, new messages will no longer be delivered to your box, and they will bounce back to the sender. In order to avoid this happening, there are two things you can try to fix this problem.
-Make sure your email client is NOT set to leave messages on the mail server. To check this, go here, and choose your email client.
-Log into your email account via the webpage. This will allow you to see a list of all messages that are waiting in your mailbox. You can optionally delete any messages you no longer need. - Updated: March 18, 2002