openvpn static route vpn

Good afternoon. An incomprehensible problem, there is a home network behind the router and the client behind it is the address 172.20.21.99. I can not understand why the address 172.20.21.99 is not available for the client. On router openvpn-server: ip r show: 172.20.21.99 via 192.168.6.2 dev...