Changes since SOA version
IXFR is a zone transfer request that returns changes since a specific SOA version. Enter the SOA version to request changes since then.
Not an apex domain
The domain NNZGVddoU7o is not the root of its zone.
Instead, try zone transfer on NNZGVddoU7o. .
Instead, try zone transfer on NNZGVddoU7o. .