Do this on SSH command line:
cp /home/apache/conf/webmails/webmail.conf /home/apache/conf/defaults/ (answer yes to overwrite)
rm -f /home/apache/conf/webmails/webmail.conf
touch /home/apache/conf/webmails/webmail.conf
chattr +i /home/apache/conf/webmails/webmail.conf
service httpd graceful
It will work then
