The screen stays dark after I end a call

When you hold your device to your ear during a conversation, the screen is turned off to prevent you from unintentionally activating the touchscreen. If you experience that the screen is not turned back on when you move the device away from your ear, try the following:

• As a temporary solution, press the power key lightly. If the screen isn't turned back on, press the power key again.
• Make sure that you have removed the temporary protection film that covered the screen when you first bought your device. The film is only designed to protect the screen during shipping and is easy to peel off.
• If you have applied a screen protection film on your device, make sure that it is specifically intended for your Xperia model. It is important that the screen protection film has holes that are accurately placed so that the proximity sensor is not blocked. To verify the exact location of the proximity sensor for your Xperia model, refer to the overview illustration in the User guide.
• Turn off your device and then turn it back on. By doing this you turn off all running applications and free up memory, which sometimes automatically solves the issue.
• Update your device to ensure that you have optimal performance and the latest enhancements.
• It is recommended to back up and synchronize your important data with a Google account.
• Use the Xperia Companion computer application to perform a software repair to reset your device. Note that all data is deleted from the internal storage of your device when you perform a software repair. Content that you have saved on an external SD card, such as photos, videos and music, is not deleted.

 To back up your data using a computer 

 To back up and synchronize apps, phone settings, and call history 

 To repair the device software using Xperia Companion