@TusharKha012 not enough just starting the Session, you must have the ShareErrorsFromSession middleware also:
An $errors variable is shared with all of your application's views by the Illuminate\View\Middleware\ShareErrorsFromSession middleware, which is provided by the web middleware group. When this middleware is applied an $errors variable will always be available in your views, allowing you to conveniently assume the $errors variable is always defined and can be safely used.