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 ab16f331fcbf8f833346-9280e4ff6d79d2d3455f2f843c3310d4.r0.cf2.rackcdn.com is not the root of its zone.
Instead, try zone transfer on dscg10.akamai.net .
Instead, try zone transfer on dscg10.akamai.net .