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 217-20-196-64.ch-zh1.pool-ewcs.ch is not the root of its zone.
Instead, try zone transfer on ch-zh1.pool-ewcs.ch .
Instead, try zone transfer on ch-zh1.pool-ewcs.ch .