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 _5C03A63B008772244D4F5DDEAC51B806.mailk1.ciberserver.com is not the root of its zone.
Instead, try zone transfer on sectigo.com .
Instead, try zone transfer on sectigo.com .