No connection

So in my clan there is a clan member that is "online" since the weekend, the problem is is not really there, when i try to play together with him this message appears: "The following user is not connected to the current server". And when i try to see in what server he is, it says "No connection". I thought "maybe he left the clan" so i checked the clan page he's still there in the clan, no message in the membership log but if i see his character profile in game it says he is in another clan.
Can someone fix/explain why this happen/say if it also happened to you or a friend? please