The only think i can think of is that he has you on his ignore (enemies) list, which likely stops you from sending him messages (i really wouldn't know, because i have never ignored anyone, nor noticed that anyone has ignored me) but that would be my only idea.
(ocultar) ¡Juega una partida en tiempo real contra un adversario conectado! Tan sólo debeís seleccionar por defecto la acción "Mover y permanecer aquí" y ¡recargar la página con la tecla F5! (TeamBundy) (mostrar todos los consejos)