In order for the HDMI lighting adapter to work, you must connect the USB cable to a power source such as a laptop or wall charger. The need for a power supply is quite odd as I've seen HDMI to Lighting cables that don't require a power supply. The adapter worked with my iPhone 12 but apparently not with my iPhone Xr. After an hour of trying, I was close to giving up the Xr and left it plugged in because I didn't need a monitor at the moment. About an hour later (only 2 hours) it suddenly worked and an iPhone Xr appeared on the screen. Not sure why it took so long, maybe the Xr needed to be 100% charged to work? Incidentally, the operating instructions forward you to a website that then asks you to download the app from the AppStore. The information about the app in the AppStore is in Chinese so you can't figure out what its purpose is and the app has a 1.5 star rating so I didn't download it as it's obviously useless.