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 rvehkppjn5duq6und34tgj71l7ks04do.dnsfactory.dk is not the root of its zone.
Instead, try zone transfer on dnsfactory.dk .
Instead, try zone transfer on dnsfactory.dk .