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 gpk01b6tngf6pb4kgqekt6heomi7hsor.resennet.dk is not the root of its zone.
Instead, try zone transfer on resennet.dk .
Instead, try zone transfer on resennet.dk .