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 25bil7ban54mk8lf057bd7821b058uln.letsvisualize.dk is not the root of its zone.
Instead, try zone transfer on letsvisualize.dk .
Instead, try zone transfer on letsvisualize.dk .