I'm trying to setup surebackup/sandbox, but I think there is something I'm missing, and I cannot see it !

This is my environment:
Production network: 192.168.254.0/24
Production VM used in my test: 192.168.254.221
production Veeam proxy ip: 192.168.254.173
Isolated network: 192.168.253.0/24
isolated network proxy ip: 192.168.1.1 (automatically assigned by setup wizard)
static ip mapping: 192.168.254.204 --> 192.156.254.221
on VBR and on my pc added the static route
route add 192.168.253.0 mask 255.255.255.0 192.168.254.173
I cannot ping the VM in isolated network
ping 192.168.253.221 destination unreacheable
ping 192.168.254.204 (static ip mapped) timed out
On involved systems there is no active firewall, and are all Windows machines.
How can I troubleshoot ?
thanks in advance
Davide