Hi, sometimes the ports especially the one near the LCD on the left do not work. For example, I plugged in the Apple charging cable but it was not charged. I plugged in an external SSD and TimeMachine said I had no backup drive. When I checked the desktop, I found that the SSD was not mounted. I had to unplugged and plugged the draive to the next port for it to work. Do other users of this machine has this problem? What could have gone wrong?