Renew certificate with expanding domains

ahh but when i try and add mail.domain.com to the string it fails and I get that ugly auth error I was getting earlier…

Domain: mail.linuxnutz.com
Type: unauthorized
Detail: Invalid response from
http://mail.linuxnutz.com/.well-known/acme-challenge/iXwptyZJsUlniy2g3PrFL-cQ4dG1Uaz_6cKYDm3APEU:
"

404 Not Found

Not Found

<p"