I have a Google Cloud Classic Application Load balancer connected to 2 fortigate appliances as backend, each fortigate has 3 nic, mgmt, trust,untrust. however the primary nic of the fortigate appliances in the mgmt nic, but the GLB is on the untrusted VPC, we cannot see any traffic from the GLB going into the fortigate, meanwhile in the GCP logs we can see that we are getting a response from the mgmt ip, any idea what to do?