giaddr erorr in DHCP server

Hello! I have vpn server based on strongswan and I want to clients requests virtual IP’s from RouterOS dhcp pool. Unfortunately, when client requests ip address from RouterOS, in logs rises up next error: “received discover from 7A:A7:CB:D8:E6:4A with unknown giaddr 10.0.10.2”
What I done wrong and how can I fix it?