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 241.55.207.91.olimp-uac.ua is not the root of its zone.
Instead, try zone transfer on olimp-uac.ua .
Instead, try zone transfer on olimp-uac.ua .