My playback server is no more seen on my wd tv live

My wd tv live works fine with internet (and is up to date) and is able to seen in the file folder my two mac (mountain lion).

But when I go to video or picture I don’t see anymore my Playback folder.

On my mac I have playback installed and  updated.

I don’t knwow what to do, it used to work fine before.

Sorry for my english and thanks for helping me

Please confirm:

1- The model number of the media player

2- The firmware version