[Opendnssec-user] Error

[Bryton]

  I am getting this error when signing my zone.

Found RRs for xxx.xxx.co.tz (bo8ab4f09kaijcqoe2ugg2oqd4snk3rl.tz) which 
was not covered by an NSEC3 record

I want to understand what it means.

I removed the A record for xxx.xxx.co.tz and sign it works but since 
removing its not an option I did put it back and resign and it was ok 
again this time.


Now I would like to understand what is the meaning of this.

-- 
Regards,
Bryton.