When I first set up CainManor on slicehost, e-mail wasn’t working. The solution, based on this thread, was to install postfix.
apt-get install postfix -Install postfix
mydomain = cainmanor.com
myorigin = cainmanor.com
mynetworks_style = host
service postfix start -start the service to see if it works as expected.
chkconfig –list postfix – make sure it will start on boot. The default install takes care of this