6tbu42qfql3lofdgra5wx47iv5cziaoaja22o5edztbrusswn7ka.mx-verification.google.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 6tbu42qfql3lofdgra5wx47iv5cziaoaja22o5edztbrusswn7ka.mx-verification.google.com is not the root of its zone.
Instead, try zone transfer on google.com .