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 f.gandi-ns.net.8.9.b.4.1.0.0.2.ip6.arpa is not the root of its zone.
Instead, try zone transfer on 8.9.b.4.1.0.0.2.ip6.arpa .
Instead, try zone transfer on 8.9.b.4.1.0.0.2.ip6.arpa .