Not an apex domain
The domain ntpham1.ntppool.net.0.e.2.3.0.0.2.4.0.b.4.1.0.0.a.2.ip6.arpa is not the root of its zone.
Instead, try zone transfer on 0.e.2.3.0.0.2.4.0.b.4.1.0.0.a.2.ip6.arpa .
Instead, try zone transfer on 0.e.2.3.0.0.2.4.0.b.4.1.0.0.a.2.ip6.arpa .