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 ec2-50-112-252-84.us-west-2.compute.amazonaws.com is not the root of its zone.
Instead, try zone transfer on us-west-2.compute.amazonaws.com .
Instead, try zone transfer on us-west-2.compute.amazonaws.com .