Error getting plugins from server

Hi everyone,

I am trying to get and install plugin from marketplace in Pentaho BI server.
I can log in and go into Marketplace.
But when i go into marketplace, there is a error with message: "Error getting plugins from server" .
I try to use some different of Pentaho BI server, e.g: 4.8.0, 5.2.0.0, 6.1.0.1, but still get the error.
My computer use proxy. I don't know whether pentaho BI server doest support proxy or not?

Please help me to solve this problem.

Many thanks,