reverse dns delegation issue

[Carl Byington]

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If we try
  dig -x 204.13.6.88 +trace
we get
dig: couldn't get address for 'ns3.digiportmiami.com': failure

but 
  dig ns3.digiportmiami.com. +trace
does find the A record from the .com servers.

Something is wrong, but I am not seeing it. Any suggestions?

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