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 b60bc9e1bb2c4e29ac75bdd628e2bf27.pacloudflare.com is not the root of its zone.
Instead, try zone transfer on pacloudflare.com .
Instead, try zone transfer on pacloudflare.com .