App was totally working locally however after deployment via heroku it started to throw internal server error. Just one time app worked via heroku and then again it started to give internal server error. Then i tried to find the source of error and i found the express-session is crashing my app when it is deployed via heroku.
Edit: App doesn't crash in the middle of the process, it doesn't totally work. No path is working. Every path throws internal server error because of express-session.
Sorry i forgot that i still have this question. I solved the issue. Problem was the session secret. I didn't realize that my .env file is in gitignore file and session was not taking secret from .env so i added a heroku config, named SECRET and that's the solution.
