Existing IP addresses may be highlighted on the Account Settings page, and then selected for deletion, using the button.  Clicking on the Update Settings button will permanently remove them from the Account Settings page.

Multiple IP's may be highlighted within the list using the "Shift" and "Ctrl" keys, allowing you to delete them at the same time.

If the default Multicast IP of 255.255.255.255 has been deleted, you may re-add it referring to Multi Range IP Addresses for more information.