can not trun on

First solution: Force restart your iPhone X.

If this process is successful, update all apps on your iPhone X to remove bugs.

Second solution: Perform a recovery mode to fix the black screen of death on your iPhone X.

In order to carry out this process, you’ll need to prepare a Mac or Windows computer with the latest iTunes installed. Also ensure that your computer runs on the latest operating system that is compatible with your iPhone X. If all requirements are met, connect your device to the computer using the Apple-supplied USB/lightning cable. Then allow iTunes to sync with your iPhone and backup files, if possible. Once the backup is secured, follow these steps to put your iPhone X in recovery mode and then restore iOS in iTunes:

1. Press and release the Volume Up button quickly.
2. Press and release the Volume Down button quickly.
3. Then press and hold the Power/Side button once prompted with Connect to iTunes screen. Do not release the button when Apple logo appears as you will need to enter recovery mode state.
4. Once you enter the recovery mode, you’ll see either Update or Restore option.
5. Select Restore if you want to reinstall and download iOS on your device without erasing data.

Do not disconnect your phone and keep it connected until the entire restore process is finished.

Did you follow the instructions in the article link at the top of the page?