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 f6bjbv7656n03fuce0ocq9j01mmdg3n0.boerneloppen.dk is not the root of its zone.
Instead, try zone transfer on boerneloppen.dk .
Instead, try zone transfer on boerneloppen.dk .