HELP - Need a DNS Guru

["Keith Goettert" <Keith@EcologyEnergy.com>]

Ns1.helpfulhome.com is the DNS server for a variety of email and
websites.  I have been having trouble lately with email arriving late
(several days) or not at all.  As far as I can tell, this is a new
issue.  I am concerned because locally the DNS server appears to be
working fine.  But when I issue commands like:

   dig ns1.helpfulhome.com @ns1.covad.net

I don't get an answer section.  I have double checked my forward and
reverse entries and all appears correct.  Can somebody give me a clue??