I'm gold and can't ranked duo with my platinum friend

Hello everybody, I was unranked last season ( i made a break of LoL ) and my friend was Diamand 5 . With the new season, i got placed to G4 and my friend P2. I would play with him but the client tell me we can't duo together. Is this a bug? I read that platinum players could play with gold players. Thanks
Report as:
Offensive Spam Harassment Incorrect Board