Try doing a full charge (approx. 5h) then do a full 2-min restart (see here) ''Open the SIM card slot cover. Using the tip of a pen or similar object, press and hold down the OFF button for 120 seconds, ignoring any vibrations, and then release the OFF button. Charge the device until a charging icon appears on the screen. Turn on your Xperia™ device''
Hello, Are you getting a "Force Stop" of the email app ? It happens when you go back to your homescreen only ? Try clearing Email data by going to settings --> Apps --> Find Email --> Clear data & cache