I have a new 13" XPS (9370) running Ubuntu. I have been using an external monitor with a USB-C -> HDMI adapter. The other day, the adapter stopped working in one of the USB ports, but still worked fine on the other two ports. Then today, it stopped working on all three ports. The computer no longer recognizes that anything was connected, even though the cable is attached and the monitor is turned on. All three USB ports work with the computer's power adapter.
Any idea what could have caused this to stop working?