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 d17bec99-us-west-2.smtp.myworkday.com is not the root of its zone.
Instead, try zone transfer on smtp.myworkday.com .
Instead, try zone transfer on smtp.myworkday.com .