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 b356ac18-a24f-4210-976e-f61b028a6e24.auth.acme-dns.io is not the root of its zone.
Instead, try zone transfer on auth.acme-dns.io .
Instead, try zone transfer on auth.acme-dns.io .