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 61-25-33-186.ufinet.com.sv is not the root of its zone.
Instead, try zone transfer on ufinet.com.sv .
Instead, try zone transfer on ufinet.com.sv .