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 *.18.121.IN-ADDR.ARPA is not the root of its zone.
Instead, try zone transfer on 121.IN-ADDR.ARPA .
Instead, try zone transfer on 121.IN-ADDR.ARPA .