Not an apex domain
The domain 64-121-118-139.s1673.c3-0.smt-ubr1.atw-smt.pa.cable.rcncustomer.com is not the root of its zone.
Instead, try zone transfer on atw-smt.pa.cable.rcncustomer.com .
Instead, try zone transfer on atw-smt.pa.cable.rcncustomer.com .