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 ddi-gm.itsc.cuhk.edu.hk is not the root of its zone.
Instead, try zone transfer on itsc.cuhk.edu.hk .
Instead, try zone transfer on itsc.cuhk.edu.hk .