Play a Friend not working

Even when me and my friend is in online, we cant play a challenge by requesting using option play a friend.

You're talking live chess, right?  Pretty sure I read somewhere that you both have to be logged into the live server for it to work.  Hope that helps...

Yes, live chess. But i am not sure, how to check we logged into LIVE SERVER? could you tell me how?

 Under the Play menu (at the top or side depending on how you have your menu oriented), just click on live.  That takes you to the live server.  If you are both over there when the challenge is issued, it should work (or so I've read).  Of course they just found a bug in the Daily challenges so who knows...

thanks buddy..

Glad to help...