I try to set up Ciscio 850 router behind the nat and allow clients to create VPN tunnels to it. I forwarded ports UDP 500 and UDP 4500 on NAT router to Cisco device. I get the following error on IKE phase 2: ISAKMP:(2022): IPSec policy invalidated proposal with error 1024. What does it means and how to fix it? This proposal is accepted when i make direct connection to Cisco device without nat presence!