Can't Initiate Wifi Sync From iPhone

I use a Mac Mini as my media center PC and to sync my iPhone and iPad via Wifi. Recently I upgraded to the new model and to Mountain Lion. Ever since then I am unable to initial an iTunes sync from the iPhone. When I do it just says searching for mini, but eventually times out. It also wont automatically sync when it is plugged into power like it should overnight. This happens when iTunes is running and even shows the iPhone as a connected device. If I initiate the sync from iTunes on the Mini it starts after a second or two and works every time, as does plugging it in. Also I am not running any kind of software firewall on the Mini that would be blocking incoming connections. Does anyone know what could cause this or anything to try to resolve it?

Thanks