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 c-68-84-169-3.hsd1.mi.comcast.net is not the root of its zone.
Instead, try zone transfer on hsd1.mi.comcast.net .
Instead, try zone transfer on hsd1.mi.comcast.net .