cdj 3000 issues with link

i have recently encountered link issues where the 2 cdj3000 players don't share info at all and not recognised. you can't access the usb from one to the other.  i tried a new usb and disconnected from my tp switch box and plugged players directly via ethernet cable which i also tried a new lead. i had to disconnect everything and power down units to get to recognise. this has happened several times now.