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 mbi3a1dfm7nvmule08av923so21bku5k.sk.eserver.net is not the root of its zone.
Instead, try zone transfer on sk.eserver.net .
Instead, try zone transfer on sk.eserver.net .