Server not responding vSphere Mobile Watchlist

I have three vCenter clusters setup in vSphere. The way I have configured access via web browser is to use load balancers to send client request connections from vsphere.domain.com to any of the three vcenters. There's no priority on which real server gets the client request. Source IP Persistence (stickiness) is set to 1 hour and the load balancers are configured to redirect to port 9443 from 80. This all has worked well both on our local network as well as outside our local network using a web browser. Now we're trying to use the Android vSphere Mobile Watchlist app to access and manage vSphere. On our network if I use the real server IP addresses bypassing my load balancer setup the android app works however, when using the FQDN (vsphere.domain.com) I immediately get "server not responding". What could the app be requesting or using that I need to account for? Different port or protocol? Thank you in advance for any information.