With regards to the calibration sensor, we request you to recalibrate the screen if you feel that the screen orientation does not respond properly to the way you hold HTC One X.
1. Go to Settings, and then tap Display, gestures & buttons (or Display & buttons).
2. Tap G-Sensor calibration.
3. Place HTC One X on a flat and level surface, and then tap Calibrate.
4. After the recalibration process, tap OK.
In response to the proximity sensor, if you are using the screen protector, please check whether the proximity sensor is not covered or blocked.
If the issue still persist, boot the handset in safe mode and try using if for at least 24 hours with the third party application.
PURPOSE of safe mode : Safe Mode is a method that allows the device to run without non-essential applications. Before booting the phone in Safe Mode, please make sure you disable the Fast-boot option by going Menu>Settings>Power>Fast-boot. To boot your handset in Safe Mode, please turn it off and then back on.
STEPS for safe mode:
1. Press and hold 'Power key' > 'Restart' > now confirm once again by taping on 'Restart'.
2. As the device restart and give you the "HTC quietly brilliant" screen with the start up sound, press and hold 'Volume down key' until you get the home page on the device with Safe mode written on the bottom left of the screen.
To turn the device out of Safe mode just restart the device. If you notice your phone works just fine while in Safe Mode, this conflict should be caused by one of the third party applications installed in the phone.
We would recommend you to uninstall the application and reinstall each application individually everyday to figure out as which application is creating this issue.
For further assistance and accurate resolution, kindly provide us the serial number and IMEI number of your handset as we are unable to locate the same.
To retrieve the above mentioned information, please follow the below mentioned steps:
From the home screen tap 'Menu' > 'Settings' > 'About phone' > 'Phone identity'. You can also press *#06# on your device to retrieve the IMEI number. You can check for the IMEI and Serial Number on the phone bill and box.