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 5b18aa434331c517903d3607818360d9.31b40a1110fa7823e9069cda9ba90594.hkfytofvydh2qdbejxzb.sectigo.com is not the root of its zone.
Instead, try zone transfer on sectigo.com .
Instead, try zone transfer on sectigo.com .