[CLIENT] Unable to connect to chat, you may reconnect manually. When game still work well

This happened when I switch my PC to another place, with the Comcast wifi internet. I can play the game normally and see people talking in the game, but I cannot chat when I select champion. I have restarted the PC for several times, and also re-install the game, still not work.

It makes me unable to play rank, what should I do? Is it because the update of the 04/28/2015?