How to fix "Cannot connect to camera" on the Android mobile phone

It stopped working a day later, I've just tried a fix

  Go to Settings > Apps,Camera, and then touch Force stop.
  Go to Settings > Apps, Camera, and then touch Clear cache.
  Go to Settings > Apps, Camera, and then touch Clear data. Caution: Any data saved in this app will be erased.

Then restart your device without opening the camera or any other applications that use the camera

It has worked so far for me.