Master Server with Proxy Server

I'm trying to connect with my own master server when the port on route was blocked.

First, i set up a normal connection with master server

Code (CSharp):

1. MasterServer.ipAddress = "xx.xx.xx.xx";
2. MasterServer.port = 23466;
3. Network.natFacilitatorIP = "xx.xx.xx.xx";
4. Network.natFacilitatorPort = 50005;

Then i request host list:

Code (CSharp):

1. MasterServer.RequestHostList ("TestConnection");

If route block my port, i detect it on: void OnFailedToConnectToMasterServer (NetworkConnectionError info)
Then change to useProxy server on this function

Code (CSharp):

1. void OnFailedToConnectToMasterServer (NetworkConnectionError info)
2.  {
3. //-- Something here
4.  
5. Network.proxyIP = "xx.xx.xx.xx";
6. Network.proxyPort = myPort;
7. Network.useProxy = true;
8.  
9. MasterServer.RequestHostList ("TestConnection");
10. }
11.  

But nothing happen at the second request host list.

Can anyone help me solve this problem

P/s: I'm not good at English, so sorry for my mistakes in this post !