All of the emails in root are error emails not emails being sent in and arriving there though catch all or such.
They are all either UBE messages
This is the mail system at host domain-web.co.uk.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to <postmaster>
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<email@example.com>: mail for localhost.co.uk loops back to myself