If you are testing an email problem and see this error:
R=lookuphost defer (-1): lowest numbered MX record points to local host
This means the domain name is not listed in /etc/localdomains
You generally can fix this by running /scripts/mailperm
If not, you should check /var/cpanel/users/USERNAME and make sure there is a DNS line in for this domain name and it is not along the lines of XDNS
Example
root@server8 [~]# mail -v test@server.com Subject: test test . Cc: LOG: MAIN <= root@server.server8.com U=root P=local S=391 root@server8 [~]# delivering 1K2CMu-0004PY-F4 LOG: MAIN lowest numbered MX record points to local host: server.com LOG: MAIN == test@server.com R=lookuphost defer (-1): lowest numbered MX record points to local host LOG: MAIN Frozen
source: http://wiki.cpaneldirect.net/wiki/index.php/R%3Dlookuphost_defer_%28-1%29:_lowest_numbered_MX_record_points_to_local_host