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 6kosbmjlrq5faqptj3b2kq35gg0jtbgt.vjm.dk is not the root of its zone.
Instead, try zone transfer on vjm.dk .
Instead, try zone transfer on vjm.dk .