21339809d3909b2d935ab7c8a580bc3f.ff66c7b9b916dcecbb7d62ea6e3041f3.646211049.sectigo.com IXFR zone transfer

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 21339809d3909b2d935ab7c8a580bc3f.ff66c7b9b916dcecbb7d62ea6e3041f3.646211049.sectigo.com is not the root of its zone.
Instead, try zone transfer on sectigo.com .