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 b2.org.afilias-nst.ORG is not the root of its zone.
Instead, try zone transfer on org.afilias-nst.ORG .
Instead, try zone transfer on org.afilias-nst.ORG .