http://www.micro-link.net/HELP/tech/helpful/postmaster/index.html
4) 'Exceeded Storage Allocation' or 'The user(s) account is temporarily over quota'.
There are two possible causes to this error. The majority of mail servers will not allow a user's mailbox to exceed a specified size. If a user does not download their email on a regular basis, or if they receive one or more very large emails, their account may be taken over the server's maximum size. When this happens, mail sent to that address will be 'bounced' until the user downloads their mail.
This can also occur if the recipient's mail server is having difficulties. This is usually a temporary fault.
Så må man formode det er en midlertidig fejl.