TCL 4-Series Roku TV S455 will not AirPlay, Cast or screen mirror

The checks in more detail

Start with the TV's settings. Press the Home button, open Settings, System, Screen mirroring, and check the mode: Prompt asks you to allow each connection, Always allow lets known devices connect, and Never blocks them. Choose Prompt or Always allow. Make sure that the TV is on the same Wi-Fi network as the phone or laptop, and that the network does not isolate devices, since a guest network or a router setting that blocks device-to-device traffic stops mirroring.

In Settings, System, Advanced system settings, check Apple AirPlay and HomeKit, and turn AirPlay on if you use an Apple device. On the device. For an iPhone or Mac, open Control Center, choose Screen Mirroring, and select the TV from the list, entering the code that appears on the TV; for Android, use the Cast, Smart View or Screen Cast option in the quick settings, which uses Miracast. For Windows, press Windows and K to open the connect panel and choose the TV, or use the Cast option from the Project menu.

If the TV is not listed, restart the TV by going to Settings, System, Power, System restart, restart the router and turn Bluetooth and Wi-Fi off and on at the phone. Update the Roku software, in Settings, System, System update, and the phone's software. If the mirroring is choppy, move closer to the router, close other apps and use the 5 gigahertz band. Some paid apps block mirroring to protect their content, which shows a black screen. If it still fails, contact TCL or Roku support with the model number.