I am following the example to install a shared control plane on a multiple networks environment (https://istio.io/docs/setup/install/multicluster/shared-gateways/) using Istio 1.3.4 on top of Azure and K8s v1.13.11. Following the installation steps, the citadel instance running in the cluster master result in the following recurrent error:

...
2019-11-08T11:13:09.537520Z info    grpc: Server.Serve failed to complete security handshake from "10.1.0.99:37404": remote error: tls: unknown certificate
2019-11-08T11:13:09.937074Z info    grpc: Server.Serve failed to complete security handshake from "10.1.0.99:37412": remote error: tls: unknown certificate
2019-11-08T11:13:10.018011Z info    grpc: Server.Serve failed to complete security handshake from "10.1.0.99:37406": remote error: tls: unknown certificate
...

If I continue the installation and install both clusters the sleep app will only hit the current cluster. Obviously the whole thing is not correctly configured.

I made some research but I did not find any clear solution. This is the basic example for a multiple networks solution so I find it really frustrating. I would appreciate any help and guidance.