Thank you for your answers, I did this search before opening the topic but unfortunately he is not registered in the forum. I wasn't either so I guess only small part of players registers here. Is there a way to search amongst all registered players in the game?

Dear all, I have been searching on this topic, but I could not find information. Is there a way if I know player's nick (or part of the name) to search for him and contact him here, to leave him a message?