Comment 3 for bug 794994

Thank you for taking the time to report this bug and helping to make Ubuntu better.

It looks like your system is configured with an invalid hostname and domain '04' (or at least that is how postfix has been configured).

You can set this manually in /etc/postfix/main.cf (look for the mydomain parameter) - or you could re-configure your system with a valid host and domain name.

You can then complete your upgrade by running:

   sudo dpkg-reconfigure postfix

If this resolves your issue please mark this bug as 'Invalid'

Thanks