[Install Agent on DMZ] How to trouble shooting AMAgentNotRespondingOnDMZHost exception

We have a hyper-v server in DMZ and trying to add it into VMM 2012 R2 for management followed by http://technet.microsoft.com/en-us/library/gg610642.aspx

As the 443 port has been used ,we changed the port to 5985,5986 and also update port on VMM Server.

I have tried several times, but keep failure when add the server in DMZ into VMM.

I enabled debug logging of VMM and get following exception from server

at Microsoft.VirtualManager.Engine.TaskRepository.Task`1.SubtaskRun(Object state) ***Carmine error was: AMAgentNotRespondingOnDMZHost (426) *** test.mydomain.local ** [s#370cc] Task`1.SubtaskRun(this: (Task`1#2b), TaskID: (guid) 101a000e-3869-436a-9e20-eec5f1cd5b55) in Task.cs:line 252 Full call stack from when the exception was thrown:  at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)     at ystem.Environment.get_StackTrace()     at Microsoft.VirtualManager.Utils.CarmineException..ctor(ErrorInfo error, Exception innerException)     at Microsoft.VirtualManager.Engine.Adhc.AddAgentTask.ThrowCarmineException(ErrorInfo error, Exception innerException)     at Microsoft.VirtualManager.Engine.Adhc.AddAgentTask.CheckIfInstallRequired()     at icrosoft.VirtualManager.Engine.Adhc.AddAgentTask.InstallAgentIfNeeded()     at icrosoft.VirtualManager.Engine.Adhc.AddHostAgentSubtask.SubtaskThreadFunction()    at icrosoft.VirtualManager.Engine.Adhc.AddAgentTask.RunSubtask()     at icrosoft.VirtualManager.Engine.TaskRepository.SubtaskBase.Run()     at icrosoft.VirtualManager.Engine.Adhc.AddHostSubtask.InstallAgent(Host lockedDbHost)    at icrosoft.VirtualManager.Engine.Adhc.AddHyperVHostSubtask.RunDeploymentSubtasks(Host lockedDbHost)     at icrosoft.VirtualManager.Engine.Adhc.AddHostSubtask.RunSubtask()     at icrosoft.VirtualManager.Engine.TaskRepository.SubtaskBase.Run()    at icrosoft.VirtualManager.Engine.TaskRepository.Task`1.SubtaskRun(Object state)     at ystem.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)    在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)     at ystem.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()    at ystem.Threading.ThreadPoolWorkQueue.Dispatch(),{101a000e-3869-436a-9e20-eec5f1cd5b55}

I  aware the issue may relate to many problems, include firewall, security... etc. 

I was wandering if there is an best practice to troubleshooting the problem.

Thanks.