My iPhone 6 Plus won't charge. I've done a reset several times, pressing the Home and Power buttons and holding them for 30 seconds, and afterward it still won't charge. I've checked to see if the port needs cleaning out and put something in there to remove any debris and still no charging. A desktop PC gives the message "USB device not recognized." Not sure what to do next. The charge cord doesn't have any damage. I've looked up some things online and most advice says to do a hard reset, which I've done without any change. Anyone know what might be the problem?