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 iad14-fa-c6r1301-fw-1-v10-n1.us6.oraclecloud.com is not the root of its zone.
Instead, try zone transfer on us6.oraclecloud.com .
Instead, try zone transfer on us6.oraclecloud.com .