Hope you are doing well and sorry for the trouble.
Do you get any error messages when the application closes? If yes, please share the screenshot of the same for a better understanding.
Would you mind sharing the version of the Acrobat Reader DC you are using? To check the version go to Help > About Acrobat and make sure you have the recent version installed. Go to Help > Check for updates and reboot the computer once.
You may also try to repair the installation from the help menu (Window Only) Go to Help > repair installation and see if that works.