Sorry this took a while to get to, I've been a lazy bastard, have checked it just now and it seems the host isn't receiving the message sent from the 2nd user, checking the debug for the send method it assigns the paddlePosY variable okay but the message just isn't either sent properly or received properly, tempted to blame peerjs but it's just a simple object being sent so might not be that, the message.getMessageObject method seems to be working as intended as well, at least it debugs out the correct variables.