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 b51hk3s46h5k9vod4gepoph7enfkunel.dbk.dk is not the root of its zone.
Instead, try zone transfer on dbk.dk .
Instead, try zone transfer on dbk.dk .