Can't access backup master from IKEv2 VPN client
I have two M370 in a cluster and IKEv2 mobile VPN for remote clients.
If connected via VPN, I am unable to Ping the management IP of the Firebox which is backup master and also I cannot open the management webpage in Port 8080 in a browser. For the master Firebox this is both working. If connected to the internal LAN, I am able to access both boxes. There are no firewall rules blocking outgoing traffic (Default policy Allow IKEv2-Users).
I think it might be a routing problem, but I am somewhat stuck. Here some details:
192.168.160.1/16 => Trusted-LAN IP assigned to both Fireboxes in the cluster
192.168.160.3/16 => Management IP Firebox 1
192.168.160.4/16 => Management IP Firebox 2
192.168.169.0/24 => Address pool for IKEv2 users