Q: My iphone 6 landscape does not work sometime

Hey QuanZheng, 

Thanks for the question and detailed information, and great troubleshooting so far! The following resource provides additional troubleshooting information for orientation issues:

iOS: Screen does not rotate

http://support.apple.com/kb/ts3805

[…]

 

2. Not all iOS apps are designed to rotate. Some may use only portrait or landscape mode, or switch depending on the content. To test screen rotation, open the Calculator app that comes with your device. If the screen does not rotate as expected while using the calculator app, continue troubleshooting.

 

3. If the issue persists, restart your iOS device.

 

4. If the screen remains locked, back up and restore your device.

 

5. If the display orientation still will not change when rotating your device, follow these troubleshooting steps.

Thanks,

Matt M.