6477C3E9EC96F50CF51BAA48E8576C20.4A167DBF8487AF835E8E24AF81FFC04B.715334903.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 6477C3E9EC96F50CF51BAA48E8576C20.4A167DBF8487AF835E8E24AF81FFC04B.715334903.sectigo.com is not the root of its zone.
Instead, try zone transfer on sectigo.com .