irb-3.core2.atl.core.mtmsys.us IXFR zone transfer

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 irb-3.core2.atl.core.mtmsys.us is not the root of its zone.
Instead, try zone transfer on mtmsys.us .