Encountered in the game world PVP is normal, but friend pvp always fail.

Now we are in the game to choose global players in PVP, connection is normal, the game can run normally.
But, when we choose the friend pvp , the initiating party always will receive a failed messages, connection is broken.
Sometimes, the initiating party use VPN connection, the game can run normally.
I don't know whether by Photon network problems .
I caught a network packet when friends PVP failure. http://pan.baidu.com/s/1gfuIJV9